Author Topic: No heat from Aquahot at the Furnace Registers  (Read 2824 times)

Bruce Sieloff

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No heat from Aquahot at the Furnace Registers
« on: October 16, 2018, 12:23:50 AM »
Aquahot AHE-100-02S had a coolant loss of about 9 gallons from an unattended leak. After refilling the AH through the filler cap and checking for pressure I now have no heat to the furnace. I tapped the check valves and the pumps seem to be running. I have hot fluid though the hoses outbound from the check valves but still no heat at the heat registers (hoses cold). The shore power electric element is working fine; we have hot water but no furnace heat. Fan switches are on, fans run but blow cold. No heat at any zones so an obstruction in all three is unlikely. Are there check valves downstream from the Aquahot?

David T. Richelderfer

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Re: No heat from Aquahot at the Furnace Registers
« Reply #1 on: October 16, 2018, 01:33:10 AM »
Yes, there are check valves.  From the maintenance manual, page 20:

"Check Valve:
Check valves are installed into the zone outlet ports for each
heating loop to ensure that the antifreeze and water heating
solution only flows in one direction. If the heating solution
attempts to backflow into the boiler tank, the check valve
closes to prevent that from happening.

"Troubleshoot the check valves if the following condition has
occurred:
 There is a lack of interior heat in a particular zone.

"NOTE: Before Troubleshooting the zone check valve it is
important to remember that if the zone circulation pump is
air locked
, or if there is a kink in a zone heating loop plumbing
line, the customer will experience the same symptoms as
a stuck check valve."


http://www.aquahot.com/files/service_manual/AHE-100-02S%20Service%20Manual%20Rev.%20B%209-27-2011.pdf

Download the file and go to page 20.  There is more - about 3 pages - on the subject.
2004 Beaver Marquis Sapphire

I had a dream... then I lived it!

Marty and Suzie Schenck

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Re: No heat from Aquahot at the Furnace Registers
« Reply #2 on: October 16, 2018, 03:48:58 AM »
Bruce, go to rvhydronicheaterrepair.com and research bleeding the system. Marty


Bruce Sieloff

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Re: No heat from Aquahot at the Furnace Registers
« Reply #3 on: October 16, 2018, 03:56:02 AM »
David, thanks for pointing me in the right direction. I suspected that the system might be airlocked and after reloading 9 gallons of fluid I see the caveat that you shouldn't let it fall below 11 in a 15 gallon capacity or run the risk of an airlock. I need to decide if I want to get the system running or fix the leak, which doesn't leak much, just steady and appears to be pretty inaccessible. A permanent fix may have to wait until winter quarters in California. I may have to find a low pressure air source, my compressor off the coach runs at 105psi and my little Kobalt at 150 psi so I appears I am over gunned at this point. This looks like one of those procedures where a tail with a hand on it would come in handy. I will see if I can procure a cooling system test system.

Doug Allman

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Re: No heat from Aquahot at the Furnace Registers
« Reply #4 on: October 16, 2018, 03:55:59 PM »
Bruce, the key of any hydronic system is to be able to get fluid into all the lines. Normally the units pumps will not do it and result in an air lock.
If you can access a small pump and pump from a bucket of antifreeze with a return line on other end of pump back into the antifreeze bucket, do one zone at a time you can flush out any air and have full fluid lines. This is way we do all our hydronic boilers when they wont flow. Does not take a lot of pressure just a pump that can move the fluid.
Pump at Home Depot usually cost around $130.00 and get two washing machine hoses for each end of pump. Pump has many uses around your shop.  Hopes this helps.

Bruce Sieloff

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Re: No heat from Aquahot at the Furnace Registers
« Reply #5 on: October 17, 2018, 01:29:36 AM »
Well I ran through the bleed instructions in the manual with mixed results, I have strong heat in zone 3, medium in zone 2 and hot pipes and cold air in zone 1. I had heat coming through zone 1, which I bled first, but then lost it after I turned it on after bleeding zones 2 & 3.. I noticed the incoming and outgoing hoses in the forward register under the console were hot but had no heat coming from the heat exchanger so I'm a bit baffled. And frustrated. Not sure what would cause this, I have no heat in the other two zone 1 registers. Fans work fine, just no heat. >:(

David T. Richelderfer

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Re: No heat from Aquahot at the Furnace Registers
« Reply #6 on: October 17, 2018, 01:35:58 AM »
Are you continuing to add coolant to the Aquahot as you push coolant through the air-locked pumps, hoses, and registers?
2004 Beaver Marquis Sapphire

I had a dream... then I lived it!

Bruce Sieloff

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Re: No heat from Aquahot at the Furnace Registers
« Reply #7 on: October 17, 2018, 07:14:41 AM »
Yes, I continually recycled the coolant, drawing out a couple of gallons at a time and then putting it back into the tank. I don't think I ever withdrew more than 3 gallons, which in a 15 gallon system should have left me with about 12.  Not sure what that translates to at the tank. The last time through I removed only about a gallon. I will give it another try tomorrow, there is always a chance that I took it below the pickup. What I don't understand is why I would have hot water entering and exiting the register heat exchanger and AH get up to full temp tomorrow and see what happens.