Tuesday, January 20, 2015

Bosch Tankless Water Heaters and Pressure Regulating Valves

  1. Pressure Regulating Valve is a valve that automatically cuts off the flow of a liquid or gas at a certain pressure. Regulators are used to allow high-pressure fluid supply lines or tanks to be reduced to safe and/or usable pressures for various applications.

  2. Bosch tankless water heaters work on water pressure and flow.  Some people experience fluctuating temperatures sometimes if they are on a well system as the well pump has a high and low setting for when the pump comes on and off.  Most common well pumps are set to like 30 - 55 psi of pressure.  So when you are using the hot water and if the pump kicks on during this time you could see a change in flow and pressure which will change the flow and water temperature out of the Bosch tankless water heater.  
  3. A Pressure Regulating Valve installed on the cold water line before the Bosch tankless water heater can be set at the low PSI such as 30 psi and then will always maintain that 30 psi consistently whether the pump kicks on or not.
  4. There are all sorts of different pressure regulating and pressure reducing valves on the market.  

Friday, December 19, 2014

Wattages and Ohms Law for Electric Tankless Water Heaters


Electric Heaters and heating elements become hot due to a voltage being pushed through a wire.  The resistance in the wire measured in Ohms creates the heat.  The more resistance the hotter the wire gets. The more voltage pushed through the wire, the hotter the wire gets. Simply the smaller the wire (or the longer the wire run) the more resistance it gives to the voltage passing through.

So as voltage increases the wattage will increase four-fold.  As the voltage decreases the wattage will decrease by a factor of 4 as well.  The below table shows the percentage of drop or gain with different applied voltages to a heating element.


Rated at 277 volts the expected wattage % is
277 applied 100% (rated Wattage)
240 applied  75%
230 applied  69%
208 applied  56%
120 applied  19%


Rated at 240 volts the expected wattage % is
277 applied 133%
240 applied 100% (rated wattage)
230 applied  92%
208 applied  75%
120 applied  25%  (1/4 wattage)


Rated at 120 volts the expected wattage % is
240 Applied  400%  (4 times wattage - Dangerous) 
208 Applied  300%  (3 times wattage - Dangerous)
120 Applied  100%  (rated Wattage)
110 Applied   84%


This is all based on Ohm's Law.

Simple Ohms Law equations are:

Amps = WATTS / VOLTS
Watts = VOLTS x AMPS
Volts =  AMPS x OHMS
Ohms = VOLTS / AMPS


A Conductor Wire's resistance is constant based on wire size and length.

A heater's watt rating is based on the wire used in the heating element and the voltage applied.

To get a 9.5 kilowatt rated heater run at 240 volts; a wire with a resistance of 6.6 Ohms is used. (If there are two elements in the heater, then each is rated at 4.75 kw and the resistance of the wire would be 12.12.)

Saturday, December 13, 2014

Calculating the Volume of Water in a Water Line

Whenever you turn on a gas, propane or electric tankless water heater the hot water starts heating up as soon as the minimum flow rate is met for the hot water demand. It takes a few seconds for the water to get heated up to the requested temperature. But, before the hot water starts to flow out of your shower or sink faucet the cold water that is in the pipe has to be pushed through your faucet. This is often referred to as pushing a "cold water slug".

Customers frequently ask us how much water is contained in this cold water slug and how long it will take to push this slug through their faucet. This can be easily calculated by using the formula for the volume of a cylinder.

The formula for the volume of a cylinder is V = Pi x r x r x h

where Pi = 3.1416; r = the radius of the water line; and h = height (or in this case the length) of the line

If your water line is 1/2" then r = .25" and r x r = .0625" and Pi x r x r = 0.19635 square inches
If your water line is 3/4" then r = .375" and r x r = .1406" and Pi x r x r = 0.4417875 square inches

Now to get all units in inches calculate h (the length of the water line) by taking feet x 12". As an example let's assume we have a 40' water line of 1/2" pipe. 40' = 480" so we calculate the Volume as:

V = 0.19635 square inches x 480" = 94.248 cubic inches

Now there are 1728 cubic inches in a cubic foot and there are 7.48 gallons in a cubit foot. Therefore there are 0.0043 gallons in a cubic inch.

So, 94.248 cubic inches * 0.0043 gallons = 0.4 gallons of water.

If you are running this cold water slug through a 1 GPM sink faucet then it will take .4 x 60 seconds or 24 seconds to push the cold water slug through the 1 GPM faucet. Add a few more seconds for the tankless water heater to bring the water up to temperature and remember that there are about 15' of internal pipe in a gas or propane tankless water heater that also starts out with cold water. In this example it will take just more that 1/2 minute to get the hot water flowing out of the faucet.

Tuesday, November 4, 2014

Bosch Neutralizers for Condensing Boilers and Water Heaters


Bosch recently has started to carry the Condensate Neutralizers for all the Bosch condensing boilers and Bosch tankless water heaters.  Condensate Neutralizers are recommended on all condensing equipment and should be serviced annually. Currently we offer 6 different JJM condensate neutralizers that cover the entire product range from the smallest output of 57,000 BTU (16kW) to the largest of 5,443,000 BTU (1,550kW).


Below is a list of what condensate neutralizer to use for each Bosch condensing boiler and Bosch tankless water heater.

The JM-2C & JM-2C PLUS can be used for any boiler or tankless water heater up to 200,000 BTU.

The JM-6C must be used for the Bosch C1210ES/ESC as it is over 200,000 BTU

Please call us at 866-289-4652 for more information and pricing.

Friday, October 24, 2014

Bosch Compress HP 200-1 Being Discontinued


Bosch has recently advised all wholesalers that the Bosch Compress HP 200-1 Heat Pump # 7736500041 is being discontinued.  Bosch is always looking for ways to improve products and while an analysis is conducted to look into options to offer a new model in 2015.  Support for the Compress HP 200-1 will still be available through Bosch Technical Support.  This item is currently out of stock.

Wednesday, October 22, 2014

Changes to Bosch Therm Outdoor Vent Kit - BTOK

Bosch is in the process of changing the color of all the Bosch Greentherm, Therm and Greenstar units to White from the old color of Silver.  This will effect the Bosch Outdoor Vent Kit - BTOK.

The new Bosch Outdoor Vent Kit - BTOK will change to white also.  Please see the new part number listed below.

 BTOK - #7736502448, (Old part #7709003213)

Thursday, October 16, 2014

Changes to Bosch Therm Gas Tankless Water Heaters

Bosch is always upgrading their products and coming out with new and better models and changes.  Below are a few new changes to the Bosch Therm gas tankless water heaters.

The current silver-gray cover will be changing to Bosch white. This change is consistent with the Bosch residential product visual branding, such as with Greenstar, Greensource, Greentherm, and Therm.  Once the inventory of the units with silver covers is sold then Bosch will start changing over to the new white covers.

Warranty updates
For recirculation applications:
The C950ES, C1050ES and C1210ES heat exchanger warranty has been improved to 10 years for the following applications:
- Controlled recirculation applications
- Combination DHW and space heating applications
This warranty statement takes affect with products produced since April 2014 (FD 420). C950ES, C1050ES, and C1210ES products produced prior to April 2014 (before FD 420) will follow the previous warranty statement.