Bosch 520HN Power & Temperature Control knobs

The new Bosch Therm 520HN that comes in either natural gas or liquid propane has 2 new control knobs for adjusting temperature and flow on the front of the heater as the older Bosch AquaStar 125 series heaters only had 1 control knob to adjust flow.

The Bosch 520HN has 2 control knobs on the front of the heater. The control knob on the left is the Power control knob and allows you to set the height of the burners for hotter temperatures or cooler temperatures. 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.

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 turning the left Power Control knob to the left will give more power and higher water temperatures. Turning the knob clockwise will give less power and cooler water temperatures.

The Bosch Pro 520 HN has a gas control 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 660EF/660EFO Tankless Water Heaters

The new Bosch Therm 660 EF and Bosch 660 EFO are direct vent units.  These units take thier combustion air from the area they are installed in.  The 660EF/EFO are compact in design for space saving installations and are only 14" x 20 1/2" x 7".  The 660EF/EFO are designed and approved for reciculation and space heating applications.  The units have electronic ignition and come equipped with built in freeze protection.  The Bosch Therm 660EF vents either vertically or horizontally using 3" or 4" stainless steel venting #AL29-4C. 

The 660EF is manufactured in Japan and comes with a different vent connection than the 830ES, 940ES, etc.  The 660EF needs to be vented with single wall stainless steel venting and is designed to connect directly to "Bosch Vent".  However, a Z-Vent adapter (Part # 2SVSWB03) allows for the use of 3" Z-vent stainless venting to be used.  Global Pro Tankless Supply carries the adapter and all the Z-Vent stainless steel venting to install the Bosch Therm 660EF.  We are the exclusive distributor for the AQ5EF Side-wall Vent Kit for the Bosch 660EF tankless water heater.

The Bosch Therm 660EFO outdoor unit comes ready for installation and does not require any additional cap or venting.

Without the Z-Vent adapter (Part # 2SVSWB03), the customer would have to purchase different venting ("Bosch Vent") to use for the 660EF.

The Bosch Therm 660 EFO is our most compact outdoor model and is loaded with features you’d expect from Bosch, including freeze protection and built-in high temperature capability (160°F).

The Bosch Therm 660 EFO is a good replacement for the GWH425HNO and the 125BO as these units have been discontinued. 

The Bosch Therm 660EF and Bosch Therm 660EFO have an excellent warranty:

• 15 year limited warranty on heat exchanger; 3 year warranty if used in direct recirculating applications

• 15 year warranty on heat exchanger if used if recirculated through a storage tank such as the Ariston mini-tank

• 5 year warranty on all other parts

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.

Bosch Therm C1210ES/ESC vs Bosch Pro GWH C920ES/ESC

Recently the Bosch Pro GWH C920ES/ESC was changed to the new model name Bosch Therm C1210ES/ESC. The model name was changed to reflect gallons per minute (gpm) at a 35 degree temperature rise. So the Bosch Therm C 1210 ES/ESC reflects a 35 degree temperature rise at 12.1 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) 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 Bosch Therm C1210 ESC commercial unit also has the ability to reach a maximum temperature of 180 degrees for commercial use.

The temperature range for the Bosch C1210ES 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.

Descaling Powerstream Pro RP17PT & RP27PT

The Bosch Pro electric tankless water heaters, Powerstream Pro models RP17PT and RP27PT are high kilowatt electric tankless heaters that heat water on demand as the water passes through them. The modules inside consist of coiled elements that heat the water. The heating elements produce extreme heat inside the modules to heat the water on demand.

The heat that is produced by the heating elements in the modules sometimes counteracts with the mineral deposits in the water. If there is a high mineral content due to a hard water area then these mineral deposits known as "scale deposits" will over time attach themselves to the heating coils inside the modules.

All Bosch Powerstream Pro electric tankless water heaters should never be descaled with any type of solution such as vinegar, muriatic acid, etc. The use of descalants flushed through the heater does not have much effect on the mineral deposits attached to the elements. Another point of trying to flush descalant through an electric tankless heater is that it will loosen some of the mineral deposits in the heater and will have a damaging effect on the flow transducer and other parts inside the tankless heater that detects the flow of water and will interrupt the signal to the circuit board itself.

The best protection against mineral deposits (scale) forming on the coils in the electric tankless heater is to check the quality of the water in your area before installing and if the water has a high mineral content then it is recommended to install a water softener or scale stopper system. The water softener or scale stopper will filter out almost all of the minerals and treat the water so the electric tankless water heater will have a longer life with less minerals building up inside.

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

Z-Flex Z-Vent Stainless Steel Vent Pipe

The Bosch Therm 940ES and Bosch Therm 830ES tankless water heaters require either 3" or 4" single wall stainless steel venting.

The Bosch Therm 940ES is a 199,000 BTU heater and the Bosch Therm 830ES is a 175,000 BTU heater. Read the manual carefully as these two heaters have been approved for longer runs using 4" Z-Flex stainless steel venting.

At Pro Water Heater Supply we carry the full line up of Z-Flex Z-Vent 3" and 4" stainless steel vent pipe. This special single wall venting is rated AL29-4C and is approved for Category I (vertical only), II, III & IV applications and is designed for use with boilers, high efficiency gas and oil heaters and water heaters where cool flue gases are vented under pressure.

Z-Vent contains a built-in, fail-safe gasket and locking band connection. No sealant is required.

Z-Vent is available in up to 24" diameter and is also used to vent boilers.

Global ProTankless Supply