Phasing out of Bosch Therm 940ESO Outdoor Unit

Bosch is phasing out the Therm 940ESO model tankless water heater in Natural Gas, Part Number 7738000001 and Liquid Propane, Part Number 7738000002.

Bosch will continue to still make the Bosch Therm 940ES NG & LP tankless water heaters. The Bosch Therm Outdoor Kit (BTOK) will be sold as an accessory for outdoor installations.

The Phase out of the Bosch Therm 940ESO outdoor unit will be immediate. Please see the list below for model numbers, color changes by manufacturing date and BTOK model numbers.

Bosch Therm 940ES NG - #7703311076
Bosch Therm 940ES LP - #7703411073
(Gray Models, FD prior to FD420 - White Models, on or after FD420)

BTOK Outdoor Kit - Gray #7709003913
BTOK Outdoor Kit - White #7736502448

Please call Global Protankless Supply at 866-289-4652 for further questions or ordering.

Bosch Therm Intelligent Cascading Kit

The Bosch Therm Intelligent Cascading Kit part number 7709003962 connects the Bosch Therm tankless water heaters together in an intelligent cascading setup.  Up to 24 Bosch Therm tankless water heaters can be connected together in intelligent cascading to deliver more GPM for each heater cascaded.

The Bosch Therm Intelligent Cascading Kit is designed to work with the following Bosch tankless water heaters:  C1210ESC, C1210ES, C1050ES, C950ES, 940ES, 940ESO, 830ES.

Please refer to the installation manual for proper installation of the Bosch Therm Intelligent Cascading Kit.

Installing the Bosch Therm High Temperature Kit #7736500074

The Bosch Therm High Temperature Kit (7736500074) allows the maximum temperature of the Bosch tankless water heater to be raised from its normal maximum of 140 degrees F up to 180 degrees F.

The Bosch Therm High Temperature Kit is designed to work with the following Bosch tankless water heaters:  Greentherm C1050ES, Therm C10505ES, Greentherm C950ES, Therm C950ES, C800ES, Integra 500, 940ES, 940ESO, Evolution 500 and 830ES.

The Bosch Therm High Temperature Kit is not designed to work with the Bosch Therm C1210ESC or the C1210ES.

The Bosch Therm High Temperature Kit is bascially some instructions and a couple Jumpers.  The installation of the kit is very easy.  There are 2 small jumpers that will be inserted on the control board in the Bosch tankless water heater.

Installing the Bosch Therm High Temperature Kit:
*Make sure power to the unit is TURNED OFF!
1.  First remove the front cover of the heater.
2.  Then remove the screws holding the control unit on the bottom of the heater.
3.  Once the control unit is detached then you can access the back of the control unit and you will see a square cutout on the back and some pins where the jumpers will be inserted.  The pins are labeled JP5, JP6, JP7, JP8 and JP2 on the bottom.  Insert the 2 small jumpers from the high temp kit into pins JP7 & JP8.
4.  Double check connections and then screw the control unit back into place and put the front cover on.
5.  Turn the power back on and the heater should default to 120 degrees F.  You will now be able to raise and lower the temperature on the unit from 100 - 184 degrees F.  Please take into consideration that when the heater is set at say, 180 degrees that the unit will only be able to flow about 1.5 - 3 GPM depending on the heater you have.  The higher the temperature the lower flow you will get.

Service Bulletins for Bosch Therm Gas Tankless Water Heaters

Bosch has a series of service bulletins for the new model Bosch Therm tankless water heaters.  These service bulletins can be very helpful with installation questions and when having an issue to troubleshoot the heater.

Please remember to be safe when working on a gas fired appliance.  Service bulletins are helpful but you can also contact Bosch technical support for help at 800-642-3111.

Link to:
Service Bulletins for Bosch Therm Units

Bosch Therm 520PN NG & LP Tankless Water Heater

The new Bosch Therm 520PN comes set for either NG (Natural Gas) or LP (Liquid Propane).  The 520PN has a standing pilot and is a naturally drafting heater and requires no power to operate.  This unit is basically for 1 major application at a time such as 1 shower at a time.  The Bosch 520 PN Needs to be vented vertically with a 5" B-vent up through the roof for a minimum of 6' to the raincap.  If the heater has to be vented out the sidewall then you must use the AQ4 Powervent kit and this kit would require 110V power.  The gas connection at the bottom of the heater is a standard 3/4" connection.

The new Bosch Therm 520PN is a direct replacement for many of the older model heaters.  Below is a list of the units that the 520PN would replace.  Please keep in mind to always be aware of gas line sizing and the length of the gas line run.

The Bosch Therm 520PN could replace:

Bosch 1600P or 1600H: (If either one of these units was vented horizontally out the sidewall with the AQ4 powervent kit then that same AQ4 powervent kit can be used for the new Bosch Therm 520PN)

Bosch Aquastar 125B, 125X, 125HX, 425PN or the 425HN: (If any of these units was vented horizontally out the sidewall with the AQ1 powervent kit then that AQ1 powervent kit WILL NOT work for the new Bosch Therm 520PN.  You would need to install the new AQ4 powervent kit for the new Bosch Therm 520PN)

ELM Le Blanc 170VP or 125VP:  (If either one of these units was vented horizontally out the sidewall with the AQ1 powervent kit then that AQ1 powervent kit WILL NOT work for the new Bosch Therm 520PN.  You would need to install the new AQ4 powervent kit for the new Bosch Therm 520PN)

The Bosch Therm 520PN is a direct replacement for the older tankless water heaters listed above but you still always want to make sure and refer to the installation manual and follow the gas line sizing chart and venting requirements.  Please also refer to local code for all other restrictions and approvals.

Bosch Therm 520PN & 520HN vs Bosch Therm 660EF

This blog entry compares the Bosch Therm series 520PN & 520HN models to the Bosch Therm 660EF heater.  The Bosch Therm 520PN & 520HN gas tankless water heaters are 117,000 BTUs as the Bosch Therm 660EF is 140,000 BTUs.  These tankless water heaters are designed for 1 major application at a time such as 1 shower at a time or maybe 2 small sinks at once. They all are available in natural gas or propane models.

The Bosch Therm 520 PN, 520HN and the 660EF all take thier combustion air from the space where they are installed in.  You will want to make sure you refer to the installation manual for these units and make sure you have enough combustion air for the area where these are to be installed.  You can always consult a HVAC technician to calculate and make sure you have enough air supply.  These units should NEVER be installed in a bathroom or bedroom where the door is normally kept closed as the heaters while running would deplete the oxygen from the room causing illness and death.  This statement is on the front of the heaters and also noted in the installation manual.  The National Fuel Gas Code states this also but the installer would also want to go by local code.

The Bosch Therm 520PN has a standing pilot light and is a naturally drafting unit as the P stands for standing pilot and the N stands for naturally drafting.  The Bosch Therm 520HN has a hydro generator ignition and is a naturally drafting unit as the H stands for Hydro generated and the N stands for naturally drafting.  The Bosch Therm 660EF requires power and plugs into 120V outlet.  The 660EF has electronic ignition and is fan assisted which makes it a direct vent unit and the E stands for electronic ignition and the F stands for fan assisted.

The Bosch Therm 520PN and the Bosch Therm 520HN both use an exhaust vent of 5" diameter double wall type B-vent and should be vented vertically up through the roof for a minimum of 6' to the raincap.  There is a vertical vent kit called the H/P VVT Vertical Vent kit and has all the material for penatrating the roof.  If venting the 520PN or 520HN up through the roof is not an option then the heaters could be vented horizontally out the sidewall but MUST use the AQ4 Powervent kit.  The 660EF is a direct vent unit and requires to be vented verically or horizontally with 3" stainless steel sealed vent pipe.  The 660EF requires a 660EF adapter first on top of the heater to accomadate the venting.

There is also the Bosch Therm 660EFO Outdoor unit and it is just the same as the 660EF but is designed specifically for outdoor installations.  The 660EFO has a special top that it exhausts out of and also has the electronic ignition and is fan assisted.  The Bosch Therm 660EF/EFO heaters plug into a 120V outlet.

Bosch Evolution 500 Tankless Water Heater

The Bosch Evolution 500 Non-Condensing tankless water heater is a top performance, gas tankless water heater from Bosch. This 199,000 BTU heater is designed for residential applications and can deliver hot water up to 140 degrees F with a 9.4 GPM flow rate at a 35 degree rise.  Not approved for space heating applications.

This Energy Star approved tankless water heater can produce enough hot water for 2-3 major applications in most homes.

The Bosch Evolution 500 is almost the same as the Bosch Pro-Tankless GWH 715ES except that the GWH 715ES does not come with the freeze protection or an external water filter screen.  The Evolution 500 has a white cover and the 715ES has a silver cover.  Both heaters are 199,000 BTU and have the same temperture rise.

The Bosch Evolution 500 heater features an electronic ignition system and can vent through either 3 inch or 4 inch diameter stainless steel vent pipe either through the side wall or up through the roof. A stainless steel concentric side-wall venting option (ESHCK-Full-Kit) is available.

The Bosch Evolution 500 heater comes with built-in Freeze Protection and is almost the same as the Bosch 940ES tankless water heater except that it also comes with a 3/4" PRV and an External Water Filter.  The freeze prevention kit is designed to provide protection for the water heater down to approximately 5°F for short term conditions only. It will not protect the appliance in areas where the temperature is routinely expected to be below freezing.  The freeze prevention kit will not protect plumbing outside the appliance from freezing.

The Bosch Evolution 500, GWH 715ES and the 940ES are wholesale model heaters and sold to licensed plumbers and contractors.  The model Bosch 2700ES is a retail unit sold to end users that would be installing the heater themselves.  The Bosch AquaStar 2700ES is the same as the Bosch Evolution and features built in freeze protection and comes with a PRV and also an external water filter screen.

The Bosch Evolution 500 comes with a limited 15 year warranty on the heat exchanger and 5 years on all other parts.  Service and labor costs are not covered.

Flow & Temperature Adjustment for Bosch Therm 330PN

The new Bosch Therm 330PN comes in either natural gas or liquid propane and has a control knob for adjusting the water flow and a slide adjustment for adjusting the heat on the front of the heater.

The Bosch Therm 330PN is a 75,000 BTU Gas Tankless Water Heater. This gas tankless water heater is for camps, cottages and low water flow applications.  The control knob on the right is the Temperature Adjustment knob and is for adjusting the flow of water through the heater which has the ability to speed the flow of water up making it cooler or slowing it down and making it hotter. The slide control in the middle is for adjusting the temperature of of the water by adjusting the height of the flame. When the slide is positioned on the small flame symbol the burners will be low and when the slide is on the high flame symbol the burners will get higher and the temperature hotter.

Below is how turning the Temperature Adjustment knob effects the heater:

Knob Position		Clockwise		Counter-clockwise
Degree Rise		90° F		45° F
Activation Rate		0.5 GPM		1.1 GPM
Max Flow Rate		1.3 GPM		2.6 GPM

As the temperature adjustment knob is turned counter-clockwise, the output temperature will lower and the activation rate of the heater will be raised. Turning the knob clockwise will raise the temperature and lower the activation rate.

When sliding the slide adjustment to the left, (small flame symbol) the heater will give lower flame and cooler temperatures and sliding the slide to the right will give hotter tenmperatures and a higher flame.

The Bosch Therm 330PN has a gas control slide that modulates burner input in response to flow. Its purpose is to ensure that the hot water temperature will remain steady, although the water flow demand might vary.

Flow & Temperature Adjustment for Bosch Therm 520PN

The new Bosch Therm 520PN comes in either natural gas or liquid propane and has a control knob for adjusting the water flow and a slide adjustment for adjusting the heat on the front of the heater.

The Bosch Therm 520PN is a 117,000 BTU Gas Tankless Water Heater. The control knob on the right is the Temperature Adjustment knob and is for adjusting the flow of water through the heater which has the ability to speed the flow of water up making it cooler or slowing it down and making it hotter. The slide control in the middle is for adjusting the temperature of of the water by adjusting the height of the flame. When the slide is positioned on the small flame symbol the burners will be low and when the slide is on the high flame symbol the burners will get higher and the temperature hotter.

Below is how turning the Temperature Adjustment knob effects the heater:

Knob Position		Clockwise		Counter-clockwise
Degree Rise		90° F		45° F
Activation Rate		0.5 GPM		1.1 GPM
Max Flow Rate		2.0 GPM		3 .7 GPM

As the temperature adjustment knob is turned counter-clockwise, the output temperature will lower and the activation rate of the heater will be raised. Turning the knob clockwise will raise the temperature and lower the activation rate.

When sliding the slide adjustment to the left, (small flame symbol) the heater will give lower flame and cooler temperatures and sliding the slide to the right will give hotter tenmperatures and a higher flame.

The Bosch Therm 520PN has a gas control slide that modulates burner input in response to flow. Its purpose is to ensure that the hot water temperature will remain steady, although the water flow demand might vary.

Bosch Therm C1050ES vs. Bosch Pro GWH C800ES

Recently the Bosch model GWH C 800 ES gas tankless water heater was changed to the new model name Bosch Therm C 1050 ES. The model name had changed to reflect gallons per minute (gpm) at a 35 degree temperature rise. So the Bosch Therm C1050ES would reflect a 35 degree temperature rise at 10.5 gpm. Along with this name change came many new features:

• Comes equipped with freeze prevention now.
• Has the capability to accept preheated water up to 140 degrees and is approved for domestic hot water (dhw), solar thermal and space heating applications in conjunction with an indirect tank.
• Has the ability to be cascaded using the Intelligent Cascade Kit for up to 24 units and would produce up to 290 gpm.

The temperature range for the Bosch C1050ES is from 100 - 140 degrees. With the use of the Bosch Therm High Temperature Kit the unit would have the ability to reach up to 180 degrees.

Announcing Our New Bosch Contractor Web Site

We are very pleased to announce that we have just opened our new web site designed specifically for Contractors and Professional Installers. Check it out at www.prowaterheatersupply.com.

On this web site we sell the full line of Bosch Therm, Bosch Powerstream Pro and Bosch Ariston Pro Ti professional tankless water heaters. These Bosch products are designed for both residential and commercial applications and are only to be purchased and installed by licensed contractors.

Of course, we also carry the full line of Bosch tankless venting and accessories.

Call us at 866.289.4652 for special contractor pricing as we are only permitted to display List Pricing on this new web site.

We also sell 3" and 4" Z-FLex Z-Vent stainless steel venting on this web site as well as the Webstone and Cimberio Isolation Valve Kits needed for tankless water heater installations.

Global Pro Tankless Supply

Bosch Therm Condensing Tankless Water Heaters

The top-of-the-line Bosch Therm Tankless Water Heaters feature a secondary condensing heat exchanger. This condensing heat exchanger is able to take the heat and energy that would be otherwise going up and out the exhaust pipe and channel that heat back into the water.

There are two main effects from this process. First, this process of reclaiming the heat before it goes out the exhaust boosts the thermal efficiency up by 10 percentage points from 82% to 92%. This means that you are paying less day after day to heat your home's hot water. Second, the heat taken out of the exhaust gases reduces the heat of the exhaust and thus allows the Bosch Therm condensing tankless water heaters to vent through PVC rather than through stainless steel. Of course, PVC is less expensive, so again the home owner saves money.

For example, the Bosch Therm C 1050ES condensing tankless water heater is a 199,000 BTU/hr maximum input unit with a 92% thermal efficiency. Not only can this heater vent out through PVC, but there is an optional concentric vent kit that can be used in either vertical or horizontal exhaust systems. In comparison, the Bosch Therm 940ES is also a 199,000 BTU/hr maximum input tankless water heater. But, as this heater does not have the secondary condensing heat exchanger it must vent through stainless steel vent pipe.

As expected, the Bosch C 1050ES costs more up front than the Bosch 940ES does. It is expected that after a few years of use the higher efficiency Bosch Therm C 1050ES will allow the home owner to recoup the higher up front capital cost.

The Bosch Therm condensing tankless water heaters all start with a "C" to indicate "Condensing." They are:

• Bosch Therm C 1210ESC (Commercial) 225,000 BTU
• Bosch Therm C 1210ES (Residential) 225,000 BTU
• Bosch Therm C 1050ES (Commercial or Residential) 199,000 BTU

Of these, the only heater that is Energy Star rated is the Bosch Therm C1050ES tankless water heater as it is below the 200,000 BTU level.

All of the Bosch Therm Condensing tankless water heaters come with a 15 year warranty on the heat exchanger and a 5 year warranty on all other parts. These heaters can only be sold to licensed installers and cannot be sold directly to home owners. They all feature an electronic ignition system and offer an optional remote control thermostat.

All three models are available in both natural gas and liquid propane and come with Bosch's patented burner design. And, they can be used in solar thermal, recirculation and space heating applications.

Call us at 866.289.4652 with your questions.

Global ProTankless Supply

Bosch Therm Tankless Product Number Changes

Recently Bosch has changed their naming strategy for the Bosch Therm line up of Tankless Water Heaters. Previously, the Bosch part numbers reflected the flow rate at a 45 degree F temperature rise; now the part numbers reflect the flow rate at a 35 degree F temperature rise.

So, for example, the legacy Bosch Pro 920ES is now the Bosch Therm  C 1210ES. This means that this heater can produce 9.2 GPM of hot water at a 45 degree F rise and 12.1 GPM at a 35 degree F rise.

This naming change was done, so it seems, to align Bosch with an emerging industry de facto standard of showing the flow rate at a 35 degree F temperature rise. In reality, showing the flow rate at a 45 degree F temperature rise made more sense as a 45 degree F temperature rise is more realistic average across the US. However, with other manufacturers advertising their heaters 35 degree F flow rate, it appeared that their tankless water heaters had a higher flow rate (which was of course not true).

So, now Bosch's published flow rates allow for easier comparisons to those of other manufacturer's heaters.

Bosch did make some upgrades to the new models, so actually the newer heaters have more capabilities than their older legacy heaters. More about those details in later blog entries...

Here is a brief listing of the name changes:

• Old: Bosch Pro 920ES  |  New: Bosch Therm C 1210ES
• Old: Bosch Pro 920ESC  |  New: Bosch Therm C 1210ESC
• Old: Bosch Pro 800ES  |  New: Bosch Therm C 1050ES
• Old: Bosch Pro 715ES  |  New: Bosch Therm 940ES & Bosch Therm 940ESO
• Old: Bosch Pro 425HN  |  New: Bosch Therm 520HN
• Old: Bosch Pro 425PN  |  New: Bosch Therm 520PN
• Old: Bosch Pro 260PN  |  New: Bosch Therm 330PN

The part numbers for the Bosch Electric whole-house and point-of-use tankless water heaters did not change, nor did the Ariston Pro Ti names change.

Call us for pricing on any of the new Bosch Therm Tankless Water Heaters at 866.289.4652.

Global ProTankless Supply