Z-Flex 6" Diameter Single Wall Stainless Steel Venting

Global Pro Tankless Supply is now carrying the Z-Flex 6" diameter single wall stainless steel venting (AL29-4C).  The 6" stainless steel venting has a male end on one side and a female end on the other with a built in silicon gasket and clamp.  The 6" diameter stainless steel venting can be used for exhaust venting tankless water heaters, boilers and pool heaters.  Below is a list of the individual items available and part numbers.

List of available 6" Diameter Venting
6" x 90 Degree Elbow Stainless Steel Venting (2SVEE0690)
6" x 4' Stainless Steel Vent Pipe (2SVEP0604)
6" x 3' Stainless Steel Vent Pipe (2SVEP0603)
6" x 30 Degree Elbow Stainless Steel Venting (2SVEE0630)
6" x 45 Degree Elbow Stainless Steel Venting (2SVEE0645)
6" x 15 Degree Elbow Stainless Steel Venting (2SVEE0615)
6" Straight Tee (2SVST06)
6" x 2' Stainless Steel Vent Pipe (2SVEP0602)
6" Stainless Steel Adjustable Vent Pipe (2SVSPA06)
6" x 18" Stainless Steel Vent Pipe (2SVEP0601.5)
6" Universal Adaptor (2SVSA06)
6" x 12" Stainless Steel Vent Pipe (2SVEP0601)
6" x 6" Stainless Steel Vent Pipe (2SVEP06.5)


Please call Global Pro Tankless Supply at 866-289-4652 for further questions or to place an order.

Z-Flex 5" Diameter Single Wall Stainless Steel Venting

Global Pro Tankless Supply is now carrying the Z-Flex 5" diameter single wall stainless steel venting (AL29-4C).  The 5" stainless steel venting has a male end on one side and a female end on the other with a built in silicon gasket and clamp.  The 5" diameter stainless steel venting can be used for exhaust venting tankless water heaters, boilers and pool heaters.  Below is a list of the individual items available and part numbers.

List of available 5" Diameter Venting

5" x 90 Degree Elbow Stainless Steel Venting (2SVEEWC0590)

5" x 4' Stainless Steel Vent Pipe (2SVEPWC0504)

5" x 15 Degree Elbow Stainless Steel Venting (2SVEEWC0515)

5" x 30 Degree Elbow Stainless Steel Venting (2SVEEWC0530)

5" x 45 Degree Elbow Stainless Steel Venting (2SVEEWC0545)

5" x 3' Stainless Steel Vent Pipe (2SVEPWC0503)

5" Straight Tee (2SVST05)

5" Stainless Steel Adjustable Vent Pipe (2SVSPA05)

5" x 2' Stainless Steel Vent Pipe (2SVEPWC0502)

5" x 18" Stainless Steel Vent Pipe (2SVEPWC0501.5)

5" Universal Adaptor (2SVSA05)

5" x 12" Stainless Steel Vent Pipe (2SVEPWC0501)

5" x 6" Stainless Steel Vent Pipe (2SVEPWC05.5)

Please call Global Pro Tankless Supply at 866-289-4652 for further questions or to place an order.

Bosch Therm External Water Filter

The Bosch External Water Filter (8703305356) replaces the internal water filter that comes with the heater. Having the water filter external means it is located under the Bosch Therm tankless water heater and is therefore easy to access and clean out. Odds are that if you do not install the external water filter then the internal water filter will not get regularly cleaned out as you would have to open the cover and remove the control board to get to the internal water filter, which is not very convenient.  It is recommended to clean the filter screen at least once a year for periodic maintenance.

The Bosch Therm External Water Filter is designed to work with the following Bosch Therm Tankless Water Heaters: C 1210 ESC, GWH C 920 ESC, C 1210 ES, GWH C 920 ES, C 1050 ES, GWH C 800 ES, C 950 ES, 940ES, 940ESO, GWH 715 ES, and 830ES.

This accessory is not included with these heaters and is highly recommended.

The Bosch External Water Filter is included with the Bosch Integra 500 and Bosch Evolution 500 water heaters.

The Bosch External Water Filter is NOT compatible with the new Bosch Greentherm C950ES and Greentherm C1050ES tankless water heaters.

Replacement filter screens part 8700507059 are available for the Bosch External water filter.  Please call us at 866-289-4652

Bosch 345/450 ESR Tankless Recirculating Heaters

The gas tankless recirculating heaters, Bosch 345 ESR and the Bosch 450 ESR are temperature modulated and have electronic ignition.  The ESR stands for Electronic ignition, Sealed combustion and Recirculating.  These recirculating heaters are designed and approved for heating and recirculating potable water in conjunction with an indirect storage tank.

The 345/450 ESR are not approved or designed for closed loop heating applications.  The ESR units are not a tankless heater as they have no flow switch to respond to flow.  Instead it’s a recirculating water heater designed for tank loading applications.  When an AquaStat (not included) hooked up to a tank tells the ESR that water needs to be brought back up to temperature, the ESR will tell a circulator (not included) to turn on to create flow through the heater to reheat the water in the tank.   Please refer to the installation and applications manual. 

The Bosch 345 ESR recirculating heater is a 95K BTU unit and can deliver 3.5 GPM at a 45 degree rise.  Efficiency is 82%

The Bosch 450 ESR recirculating heater is a 120K BTU unit and can deliver 4.5 GPM at a 45 degree rise.  Efficiency is 81%

The temperature control range for both heaters can be set anywhere from 115°F (45°C) - 190°F (90°C)

The 345/450 ESR comes with a standard ¾” pressure relief valve. 

The 345/450 ESR has a special built-in freeze prevention cycle and is controlled by a sensor.  Freeze protection is always assured by the operation of the appliance.  If the primary NTC (temperature) sensor detects temperatures 9°F below the selected temperature, the appliance starts on minimum power until the sensor reads selected temperature.  In the case of minimum set point temperature then it will start at 41°F.  The use of non-potable additives like glycol is not approved.

The Bosch 345 ESR and the Bosch 450ESR must be installed indoors according to the provided installation manual.  The 345/450 ESR is NOT approved for outdoor installations. 

The Bosch 345/450 ESR recirculating heaters must be vented in accordance with the installation manual and require Category III 3” stainless steel sealed venting for the exhaust.  These heaters are direct vent units and must be vented directly to the outside in accordance with the installation manual.  These heaters cannot be combination vented with any other appliance.  The intake should be taken from the outside and 3”PVC or other material can be used only for the intake air.

The Bosch 345/450 ESR recirculating heaters are gas specific so they cannot be converted from one gas type to another.

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 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

Bosch Therm Tankless Water Heaters

This blog is dedicated to the discussion of all things that relate to the Bosch Thermotechnology line of natural gas, liquid propane and electric tankless water heaters for professional installers.

The Bosch Thermotechnology line of tankless water heaters can only be sold to professional installers (not directly to home owners). The Bosch Therm tankless water heaters are divided into residential and commercial offerings.

Bosch Therm lineup of Gas tankless water heaters

The top-of-the-line Bosch Therm gas and propane tankless water heaters are 92% efficient and include secondary condensing heat exchangers that allow for the use of PVC exhaust piping.

When installed by licensed professionals, the Bosch Thermotechnology line of professional tankless water heaters offer longer-term warranties than are available with the Bosch Retail line of tankless water heaters.

We sell the complete line of Bosch Therm tankless water heaters through our new web site at http://www.prowaterheatersupply.com. We can also be reached directly at 866.289.4652.

We hope that you will find the content of this blog to be informative!

Global ProTankless Supply