Author Topic: circulation pump sticking in Hydrohot  (Read 2298 times)

Cloyd Robinson

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circulation pump sticking in Hydrohot
« on: March 01, 2021, 02:44:18 AM »
My hydrohot works perfectly if I use it regularly. But if I use it sporadically, the front circ pump tends to stick occasionally. I can get it working by thumping on the pump housing with a crescent wrench but it will reoccur when it wants to. Can these pumps be rebuilt or is it a dispose and replace situation?

Fred Brooks

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Re: circulation pump sticking in Hydrohot
« Reply #1 on: March 01, 2021, 12:57:42 PM »
     Cloyd,
  Seeing the difficulty to access the pump, just replace it and be done. I know it is pricey but consider the next time you need your Hydrohot, you will be annoyed and remember how much your Bride likes hot water. Hope this helps, Fred
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Eric Maclean

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Re: circulation pump sticking in Hydrohot
« Reply #2 on: March 01, 2021, 01:43:07 PM »
Cloyd
These circulation pumps are per ent magnet motors which means the magnets are made from covered metallic if you hit the outter case of the motor the magnets will crack which will distroy the motor your
Problem is likely the motors brushes are worn out and need replacement on some they are accessed externally making it a straight forward job.
If you do divide to dismantle the motor check the brushes for ware ( length remaining) and the brush springs for discolouration and strength then look over the armature for discolouration in the windings and the solder joints on the commutator also check the commutator for burn marks .and lastly look the magnets over for signs of cracks or looseness.
If all looks good clean up the commutator with some fine emery lighty grease the bearing and reassemble with new brushes
Some of these circulation pumps are very expensive but the better quality ones are serviceable in fact some you can remove the motor from the pumps wet end without loosing any coolant .
Depending on how accessable the pump is you might want to remove it and service it first at least that will give you a better feeling about it if you do have to spend heavily to replace it.
Hope this helps
Eric
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.
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Thayden Waltonen

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Re: circulation pump sticking in Hydrohot
« Reply #3 on: March 01, 2021, 05:24:44 PM »
i don't have a hydrohot, but, assuming we are talking the main circulator pump which in my 98 patriot thunder is mounted on the left hand wall of the heater compartment and circulates the heating fluid through the hurricane, the DHW and a heat exchanager from the engine coolant, it isn't hard to access at all, with the exception that you have to break into the hydronic circuit to do so and there isn't a convenient drain or refill/purge approach. I'm working on that.

meanwhile, I haven't had the circulator apart because mine works we the people. i suspect it may be a wet rotor similar to pumps provided for hydronic heating in homes except that it is designed for 12V DC. I service home installed pumps all the time and they can stick, as you describe. We don't tend to tap them but to isolate the pump with valves and remove the motor and impeller and clean the housing of corrosion (although this is a plastic housing so you might have foreign matter but you shouldn't have the housing itself corroding) and spin the impeller by hand to test resistance, bearing complications, etc.. And if it doesn't start and spin reliably once cleaned and hand turned we put a new pump (or 'cartridge' which in home heating is the replaceable wetted core of the motor and the impeller).

There are some relatively affordable DC alternatives out there. The ones closest in form factor and threading are getting up toward $200 but look at this. 2200 L/H (i.e about 9.6 GPM) with plenty of head. entrys and exits are similar in direction and location but I am unable to say what the connection style or threading is, but it if it can be chased down, well worth a couple adapters. (the hyperlink function in this forum doesn't function as i'm used to so don't know if that link will appear but the ASIN # on amazon is: B08C7PTRPD. his is not an OEM replacement but the specs seem formidable for the price if the connection can be worked out.

https://www.amazon.com/Water-Hydraulic-brushless-Boost-Brushless/dp/B08C7PTRPD/ref=sr_1_9?dchild=1&keywords=Huanyu+12V+DC+Mini+Brushless+Hot+Water+Pump&qid=1614617542&s=hi&sr=1-9

Eric Maclean

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Re: circulation pump sticking in Hydrohot
« Reply #4 on: March 01, 2021, 06:46:25 PM »
I'm not sure what these circulation pumps are texted at but I don't think it's anywhere near 9 gallons a minute I could be wrong though.
1997 Patriot Yorktown
3126-B
2009 Chevy HHR
Roadmaster falcon tow bar
Demco Air Force one tow brake.

Thayden Waltonen

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Re: circulation pump sticking in Hydrohot
« Reply #5 on: March 03, 2021, 11:33:40 AM »
@eric maclean i looked at high temp rated 2.5 and 5 gallon models as well in that price range. They don't specify the head at which they rate the circulation so I was being conservative. I'm buying a 2.5 gallon for $25 (!) as a circulator for a block heater on another truck so i will report what these 20 mm threads really are. it's easier to just buy one than try to discuss thread standards with limited english speakers (no disrespect intended, i'm glad these are available. I'd gladly pay twice or even 3 times as much to get an american one, but not 8 times as much or more.

Now that I find that the hydrohot, and perhaps the aquahot, are located far from the heater compartment, there could be a second pump but it would be similar if not as perfectly accessible. although you could consider the piping and access when you install a new one apparently you reach the old one to tap it. that 's better than some of the most nefariously located components :-)

Cloyd Robinson

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Re: circulation pump sticking in Hydrohot
« Reply #6 on: March 25, 2021, 10:52:57 PM »
I purchased a replacement pump and, of course, the old one started working perfectly. Kind of like it sensed it was about to be garbage canned and decided to pay attention to business.
I will hang on to the replacement, chances are it's just a matter of time! I do appreciate all the help!

Joel Ashley

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Re: circulation pump sticking in Hydrohot
« Reply #7 on: March 26, 2021, 01:13:49 AM »
Now, remember what Fred said:
     Cloyd,
  Seeing the difficulty to access the pump, just replace it and be done. I know it is pricey but consider the next time you need your Hydrohot, you will be annoyed and remember how much your Bride likes hot water. Hope this helps, Fred
Joel and Lee Rae Ashley
Clackamas, Oregon
36.9 ft. 2006 Monterey Ventura IV, aka"Monty Rae"
C9 400HP Cat

Cloyd Robinson

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Re: circulation pump sticking in Hydrohot
« Reply #8 on: March 26, 2021, 02:02:50 AM »
Ok. Not going to argue with Fred. Or you.  👍
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