PCB Control Boards for Powerstream Pro & Bosch Tronic 5000 Electric Tankless

The PCB control board (Printed Circuit Board) is a thermostatically controlled circuit board that allows the whole house electric tankless water heater, models WH17, WH27 & WH36, to be manually controlled by a temperature dial that would range in temperature from 86-131 degrees. The PCB in conjunction with a flow transducer enables the PCB to turn on additional elements in the heater as necessary depending on the amount of gallons per minute (gpm) flowing through the heater.

The PCB would recognize many factors in the function of the heater to maintain a steady temperature and all of this is determined on where the temperature knob is set to, the gpm flowing through the heater, and the temperature of the incoming ground water.

To obtain the maximum heating potential of the Bosch Tronic 5000 electric tankless water heater it must be wired correctly and have the full required voltage to the unit. The Bosch Tronic 5000 WH17 would require 2 independent double pole 40 amp breakers wired with 8 gauge wire and could draw a maximum of 80 amps at full flow through the heater. The WH17 would require the home to be supplied with a minimum of a 150 amp service. The Bosch Tronic 5000 WH27 would require 3 independent double pole 40 amp breakers wired with 8 gauge wire and could draw a maximum of 120 amps at full flow through the heater. The WH27 would require the home to be supplied with a minimum of a 200 amp service.  The Bosch Tronic 5000 WH36 would require 3 independent double pole 60 amp breakers wired with 6 gauge wire and could draw a maximum of 180 amps at full flow through the heater. The WH36 would require the home to be supplied with a minimum of a 300 amp service.

The maximum inlet water temperature allowed into the electric tankless is 86 degrees Fahrenheit.

The Bosch Tronic 5000 WH17, WH27 & WH36 have had many upgrades and engineering improvements over the years. In January 2007 the WH17(RP17PT) & WH27(RP27PT) went from having copper canisters that contain the heating elements to an upgraded Polymer module. The PCB control board was also upgraded to maintain a more steady temperature that works with the heating elements in the polymer modules.

Below are the designated PCB control board part numbers for the units before and after 2007.

Before 2007 with serial #60A 00000 or lower:
Powerstream Pro RP17PT PCB with copper can units, part #93-793777
Powerstream Pro RP27PT PCB with copper can units, part #93-793778

After 2007 with serial number between #60A 80000 - 107:
Powerstream Pro RP17PT PCB with polymer units, part #93-793843
Powerstream Pro RP27PT PCB with polymer units, part #93-793844

Newest Bosch Tronic 5000 units with serial number after 108:
Bosch Tronic 5000 WH17 PCB with polymer units, part #8738701732
Bosch Tronic 5000 WH27 PCB with polymer units, part #8738701738

Bosch Tronic 5000 WH36 PCB with polymer units, part #8738701744

New Bosch Tronic 5000C Pro WH36 Electric Tankless Water Heater

Bosch has just released the new Bosch Tronic 5000C Pro WH36 electric tankless water heater.  This new Bosch electric tankless water heater is capable of doing more applications at one time for the people that are limited to electric power only in their homes.

The new Bosch WH36 is capable of up to 6 gallons per minute (gpm) and can the maximum temperature is 131 Degrees F.  The unit will produce 3.5 gpm at 131 degrees max.  This new Bosch electric tankless water heater is great for people looking to do 2 different things at one time.  The WH36 has a high power requirement to heat the water as it passes through.  The unit will require a 300 AMP service to the home and will need to be hard wired in with 6 ga wire to 3 - double pole 60 AMP breakers.  Please have your installer refer to the installation manual for proper installation and power requirements.

Descaling Bosch Gas Tankless Water Heaters

All of the Bosch gas tankless water heaters both in natural gas (NG) and Liquid Propane (LP) should be descaled now and then on a periodic basis depending on the quality of the water in your area.  Some towns have low mineral content while others are very hard.  Scale is basically mineral deposits in the water that pass through the copper tubing of the heat exchanger and after heating up they stick to the insides of the copper piping and over long periods of time will restrict the flow of water through the heat exchanger causing issues and overheating. 

Global Pro Tankless Supply sells a Flow-Aide Descaling Kit that allows the user to flush the Bosch tankless water heater with not much work involved and eliminates the scale built up in the heater.

The Flow-Aide Descaler Kit comes with everything you need to quickly dissolve water scale, lime, rust, and other water formed deposits, restoring efficiency to all Bosch gas tankless water heaters.  This descaling kit will also work for all other gas tankless water heaters, boilers, etc.

Flow Aide System Descaler is a non-toxic concentrate which is certified to NSF/ANSI 60 for use as a cleaner in potable water systems. Flow-Aide is the perfect descaling solution to keep your Tankless Water Heater in good operation. Combining Flow-Aide with one of our Isolation Valve Kits (Service Valves) will make the descaling process quick and easy!

Flow-Aide is: Non-Corrosive, Non-Toxic, Fully Biodegradable*, Safe to Handle, Zero V.O.C.

IMPROVE EQUIPMENT EFFICIENCY: Water scale deposits are a significant cause of heat transfer loss, along with the subsequent increase in energy costs. In fact, even a thin layer of scale (1/32") can cause a 30% increase in the cost to operate that piece of equipment. Keeping the heating passages free of mineral deposits significantly improves efficiency, conserves energy, extends the useful life of the equipment, and saves you time & money.

The Flow-Aide Descaling Kit includes the following:

1 - 3.5 Gallon Bucket
1 - 350 GPH Pump
2 - 5 Foot Rubber Hoses
1 - Quart Flow-Aide

There is also the Flow-Aide Descaling Kit PLUS which includes the Isolation Valve Kit (Service Valves).  We also sell additional quarts and gallons of the Flow-Aide Solution.

 

Bosch Therm 520HN NG & LP Tankless Water Heater

The new Bosch Therm 520HN comes set for either NG (Natural Gas) or LP (Liquid Propane).  The 520HN has a hydro ignition 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 HN 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 520HN is a direct replacement for many of the older model heaters.  Below is a list of the units that the 520HN 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 520HN 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 520HN)

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 520HN.  You would need to install the new AQ4 powervent kit for the new Bosch Therm 520HN)

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 520HN.  You would need to install the new AQ4 powervent kit for the new Bosch Therm 520HN)

The Bosch Therm 520HN 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 Tronic 3000 Point-of-Use Electric Tankless Water Heaters

There are 5 different Bosch Tronic 3000 point of use electric tankless heaters, Models US12, US9, US7, US6 and the US3.  All models have different Kilowatt requirements and require specific breakers and wire gauge size.

Ultra compact and lightweight, these five point-of-use / under-sink tankless water heaters were designed to provide an endless supply of hot water for 1 kitchen and / or bathroom sink at a time in commercial and residential applications. Advantages include 99 % efficiency with minimal stand-by loss. Most models come equipped with high / low kW settings and universal horizontal / vertical mounting options.

The model Bosch Tronic 3000 US3 point of use electric tankless is the only unit that is 120V and is designed for low flow sinks in southern states where the incoming ground water is warmer so the temperature degree rise can be achieved by the 120V output where it will provide hotter water.  This unit is not recommended for the northern states where the incoming ground water is cooler as the unit only has the ability to use one setting as it only has one element inside the heating coil.

The model Bosch Tronic 3000 US6 point of use electric tankless is 277 volt, 6KW and gets hard wired in to a 25 amp breaker.  The US 6 is the direct replacement for the older Powerstream Pro RP2P.  The Bosch US 6 has a low/high switch that enables either 1 or 2 elements to be activated depending on the output temperature you are trying to achieve.  The US 6 is good for a point of use sink with lower flows. 

The model Bosch Tronic 3000 US7 point of use electric tankless is 240 volt, 7.2KW and gets hard wired in to a 30 amp breaker.  The US 7 is the direct replacement for the older Powerstream Pro RP7P.  The Bosch US 7 has a low/high switch that enables either 1 or 2 elements to be activated depending on the output temperature you are trying to achieve.  The US 7 is good for a point of use sink with lower flows. 

The model Bosch Tronic 3000 US9 point of use electric tankless is 240 volt, 9.5KW and gets hard wired in to a 40 amp Double Pole breaker.  The US9 is the direct replacement for the older Powerstream Pro RP1P.  The Bosch US 9 has a low/high switch that enables either 1 or 2 elements to be activated depending on the output temperature you are trying to achieve. The US 9 is good for a point of use sink/dishwasher or washing machine.

The model Bosch Tronic 3000 US12 point of use electric tankless is 240 volt, 12KW and gets hard wired in to a 50 amp Double Pole breaker.  The US12 is the direct replacement for the older Powerstream Pro RP12PT.  The US 12 is good for a point of use sink/dishwasher or washing machine.  The US 12 is thermostatically controlled.  This unit may also work for a low flow shower if installed in the southern states where the incoming ground water is warmer.

Bosch Tronic 5000 WH17 & WH27

Bosch Tronic 5000 WH 17 & WH27 Electric Tankless Water Heaters

Ideal for replacing your electric storage tank water heater. The Bosch Tronic 5000 WH17 & WH27 electric whole house tankless water heaters are compact and powerful and can be installed virtually anywhere inside the home. Advantages include endless hot water, reduced electricity costs and substantial space savings.

Designed to replace a 20 - 40 gallon electric tank. The Bosch Tronic WH17 &  Bosch Tronic WH27 electric tankless water heaters are built to last. They have Plastic Polymer Modules and brass fittings. Each heater module is protected by an electro-mechanical thermal cut-out. If the temperature of any of the heater modules gets too high (over 195 degrees), then the cut-out will trip and cut the power to that heater module. If the cut-out trips, it must be reset while the circuit breakers are off. If you are not comfortable or qualified to perform this task, consult the original installer or a licensed electrician. This cut-out will only trip in exceptional circumstances. These small electric tankless water heaters can be installed virtually anywhere in the home and, of course, produce an endless supply of hot water.

There are many changes in the new Bosch Tronic 5000 WH17 and the WH27 compared to the older models Powerstream Pro RP17PT and RP27PT.

The new improvements for the Bosch Tronic 5000 WH17 and the WH27are:

• The units overall height is shortened by 4 inches due to reconstruction and placement of the main PCB board in the bottom of the unit.  (WH17 PCB Board #8-738-701-732, WH27 PCB Board #8-738-701-738).
• The Heating element assembly modules inside the unit have been redesigned to change the flow of the water in the modules to a different angle so as to not allow the mineral deposits to build up on the elements.
• There has been new single triac and dual triac PCB boards attached to the top of the heating modules as to give the heater more sensibility and maintain a more consistant heat.  (Single Triac PCB #8-738-701-733, Dual Triac PCB #8-738-701-723).
• The Thermal Cutouts on the top of the heating modules have been redesigned to trip at a little lower temperature of 195 degrees F to keep the elements from being damaged and overheating and hurting the piping and modules.

The minimum activation rate required for the unit to activate. (Activation rates: WH17 = 0.6 GPM, WH27 = 0.8 GPM).

The WH17 & WH27 are designed for cold potable water only. These water heaters are not designed for preheated water or recirculation applications. Increase flow rate where ever possible if water is coming out too hot.

Verify incoming water supply is at least 30psi. For people on well systems, the recommended pressure range is 30-50psi.

Maximum flow rates for each unit are as follows. WH17 = 2.3gpm, WH27 = 3.5gpm.

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.

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.