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Hi, we am trying to fix Heating Problem. Having Red Zone DVS 600 Air Handler connected with BOSCH Tankless Water Heater.

In the Furnace there is Circulation Heat Pump attach to Inlet & Outlet on Heating Hot Water Coil, when ever Heating is ON then Water flowing with the speed of 0.3 gpm (gallon per minute), because of this very very slow speed of Water Flow, we are getting Cold Air from Vents (no hot Air), and we replace the new Heat Pump also, still same issue.


And this Hot Water Heating Coil is just for Heating Purpose only. On the top of this there is Evaporator Coils are there for A/C. so both are separate Coils are there.

So I want to know is there any way we can DESCALE the Heating Coil to remove all Blockage in Coils, please let me know.

Thanks

What is the water heater temperature set to?

Temperature is Set on Water Heater is 124.
Both units are connect each other.

Hot water getting fine every where in Home Showers/Tape etc, only the thing Water Flow from Heating Coils with the speed of 0.3 gpm (gallon per minute). If Water Flow with the speed of at least 0.5 gpm the Heat get from Vents.

And what is the name of this "Circular Brass on which it is written 1.5 with pen" and what is the function of this  thing in the Coils.

The taps and showers run through a mixing valve and should have a fixed temperature of 120F.

If you look at page 26 of the installation manual you need 140F water supply for a CSA P.9-11 Certified Condition.  Increase the water heater temperature to 140F.

And that part is the flow valve rated for 1.5 GPM.  You may want to try reducing the pump speed from high to low.

Thanks for your reply, in Jan-2020 one Tech come and increase the Temperature to only 126 on BOSCH Machine, after 12 hours of that time BOSCH Machine start giving problems by saying error codes C1, C2, CF, EC etc, then did many things by BOSCH Tech, none solve the problems. Then finally we replace a New BOSCH T9800 SE Machine, after this it is working fine till now with out any errors. Because of this reason to not damage BOSCH Machine, we never increase Temp over 124 on BOSCH Machine, and it is working fine till Winter 2021 & 2022 Winter till June/2022.

Now from Oct-2022 we notice Heating problem, before always it work fine for 122 temp. If we try to increase over 124 now, may be same problem occur showing many errors etc. So we are not increasing Temp on BOSCH by BOSCH Tech advice.

And the Heat pump is on High currently, still Water flow is not increase over 0.3gpm (gallon per minute). So how to increase Water Flow over 0.5 gpm in this Pump.

And if we increase Temp to 140 on BOSCH Tank, then how it will increase the Water Flow in Heat Pump. Please let me know.

The circular brass thing is your flow valve. The number written is its rated setting of 1.5gpm. Perhaps it could be the problem. How do you know your water flow is .3gpm? You do need to get the temperature up, 120 is not hot enough for an air handler coil. That Bosch should have no problem going to 140 without any issues. There may be settings that need to bypassed or adjusted if it thinks it's only being used for domestic hot water that may be preventing you from setting it to the hotter temperature.

I press the PIN after this there is no Air comes at all, just I notice 2 or 3 Water Drops came, and that Pin gone inside and it is not coming up. But I put the Brass Cap tight, so that Water should not leak from there.

And I put the Pump Speed to LOW, still same issue.

1)--before increase temp on Thermostat, we leave it Open screen in BOSCH Machine which shows clearly how many gpm. So once the screen ready then we increase Temp on Thermostat and we watch the Screen on BOSCH Machine, then it is showing in this order
1st shows 0.5gpm then drop to 0.4gpm then again drop to 0.3gpm, after this it is staying on same flow rate. And why this HEAT PUMP Drop Water Flow Rate from 0.5gpm to 0.3gmp, is there some thing wrong in this Pump, please let me know.

2)--we increase Temp to 124, still same issue, for a short time we get hot Air then we notice Cold Air coming, and inlet / OUTLET both Pipes get Cold.

Your Bosch is vented with 2" venting.  Does it exceed 60' once you count the fittings?  Undersized venting will cause the CF, C1, CE errors.  You may need 3" venting in order to increase the temperature to 140F.  Or maybe there is a blockage in the vent system, or a slope issue causing water to block the flue gasses. 

Are you able to see the water heater venting termination and make sure there is nothing blocking the intake or exhaust?  Verify there is no ice or snow inside of them.  Have a look while it's running and see if the exhaust is being sucked into the intake.  Sometimes fences are installed after installation which can affect operation.

If the GPM was that low and not starting the water heater, then I would be looking at a plumbing issue.  I have seen faulty mixing valves cause problems like this.

It does sound like you may have separate issues here.

Pipe Length Intake/Outlet Flue Exhaust Sizes: 2 inches twin pipe combination, both having 20 feet distance from Machine to outside (where as BOSCH Machine T9800 SE 160K BTU support up to 60 ft distance)
- 1 Termination plate outside.
-Outlet I have: -4 45 degree elbows, -3 90 degree elbows
-Intake I have: -2 45 degree elbows, -3 90 degree elbows
Note: Outlet & Intake both having same pipe distance.
-Outlet equipment length is 44 ft (straight pipes 16 ft & elbows 28 ft - together 44ft) – up to Flue Exhaust.
-Intake equipment length is 39 ft (straight pipes 19 ft & elbows 20 ft - together 39ft) – in to Air Inlet.
Note: each elbow calculate as 4 ft base on BOSCH calculation. That is why 20 ft Pipe length distance becomes 44 ft & 39 ft.
This all Calculation done very long time ago, and Pipe Length Distance 44ft & 39ft. And currently all Basement Renovated, there is no way to increase Pipe Size to 3", need to Damage a lot to do this Job. But Machine side all working fine Hot Water in Taps & Showers etc, we don't have any errors and Venting Distance under 60 ft.

Both Intake & Outlet both Piper are clear, no Ice/No Snow/No Fence all clear. This is new house build by Builder.

Quote from: Porcupinepuffer on February 27, 2023, 05:38:45 PMThe circular brass thing is your flow valve. The number written is its rated setting of 1.5gpm. Perhaps it could be the problem. How do you know your water flow is .3gpm? You do need to get the temperature up, 120 is not hot enough for an air handler coil. That Bosch should have no problem going to 140 without any issues. There may be settings that need to bypassed or adjusted if it thinks it's only being used for domestic hot water that may be preventing you from setting it to the hotter temperature.

what is the functionality of this "flow valve" in this Coils, that flow valve is completely sealed, there is no way to open for cleaning Blockage etc.

The flow valve comes in different sizes depending on what model of air handler you have and it's purpose is to reduce the incoming water pressure as I believe anything over 5 GPM may cause issues.

Does the air handler supply heat if you open a hot water tap at the same time?  If so, I would rule out the flow valve and look at the mixing valve as the problem.

The air handler wants 140F and there is a problem with the water heater if it cannot achieve it.

yes when we open hot water in tap we get the heating.

Hi there,
I notice some changes in my Home, when weather temperature is falling then in my Home water Pressure increases suddenly, after this I notice Heating is working fine, with out doing any changes in my Home. Then I check Water Pressure shows 0.5 or 0.4gpm.
Now it is not showing 0.3gpm, and it is showing 0.4gpm and Heating is working by itself.

Now I want to know, if again fall Water Flow 0.3gpm then How to increase Water Flow Pressure with out depends on Weather condition.

Please let me know.
Thanks.

I already Install Drain Out Tap on April-03-2023, please have a look in Photos. After this I remove Air Bubbles from my system successfully. And I did many different Testing on this system as follow below.

1)--I close Shut Don Valve, then I run Heating, after this I Open Drain Out Tap, then I notice Water flowing with the speed of 1.3 GPM (at this time I am collecting water in Bucket, I mean not going to Loop), and Heating working perfectly fine. So I notice COIL are perfectly clean and fine.

2)--But when I close Drain Out Tap & Open Shut Down Valve, after this I notice Water Flow is 0.3 / 0.4GPM. and Heating not working properly.
Now I want to know, why the Water is not Flowing in LOOP after COIL. What is the problem in Loop. And how to check "What is Blocking in LOOP System".

3)--Is this the EXPANSION TANK Issue or LOOP PIX Pipe Blockage issue, How to find out, "what is Blocking in the LOOP" which not allow to pass Water Flow back in TANK.

4)--And I did this Testing also, on COLD Pipe the new SHUT DOWN VALVE which I install leave it Open, and I close the old SHUT DOWN VALVE on Cold Pipe, after this I open newly install Drain Out Tap, but I notice there is no City Water is coming from that newly install DRAIN OUT TAP. So what is Blocking in LOOP to not flow water in either direction.

Please let me know.

Hi there, is there any export can help me,
We install New Heat Pump
we replace all PEX Pipe Loop.
we install Shut Down Valve & Drain Out Tap.
we inspect Check Valve, Flow Control, In-Line Check Valve all clear.
We did Air Bound Purge Air out from system.
we Descale Tankless Hot Water Tank.
we clean Air Filter & Water Filter in Tank.
we check Domestic Water Pressure & Expansion Tank Pressure, all good.
we increase Temp on Hot water Tank up to 140 degree.

After doing above this all, still Water Flow Rate shows 0.3gpm or 0.4gpm.


Now I want to know, is there any way I can increase Speed on Heat Pump by replacing Electrical wires on Control Board. Please let me know. Only this is the Testing left there.