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Where to get a pump for the tankless water heater maintenance ?

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  • Sep 13th, 2018 3:47 pm
[OP]
Deal Fanatic
Jun 7, 2005
8414 posts
556 upvotes

Where to get a pump for the tankless water heater maintenance ?

To my understanding, we should flush the tankless water heater annually with vinegar. Unfortunately, we have not been doing it, and some people say if there is a water softener system at home, we don't need to flush it that often. Anyway, I am thinking I should consider doing it this year. I wonder what specific water pump do I need for this job ? with what horsepower ? I do have a water pump which came from a used small water fountain home decoration. I wonder if I can use that.

If not, where is a good place to get cheap one for this job ? I remember seeing one at Lowe's which costs like $100.

By the way, the guy who installed my tankless system didn't show to where to connect the hose and how to flush it. Hopefully, it is easier enough to DIY.

Thanks for any tips and advice.
16 replies
Deal Addict
May 23, 2009
2274 posts
793 upvotes
Mississauga
Home depot, Lowes and Amazon all have utility pumps. You only need the pump to circulate the descaling liquid so your fountain pump should work fine if you can fasten a 3/4" hose.

I use the Everbilt 1/6HP submersible pump sold at homedepot, it's rated at 28GPM so more than enough flow. You also need a 5 gallon bucket and a washer hose kit. I also use a grid guard (http://www.canadiantire.ca/en/pdp/maxim ... 1379p.html) to keep the pump off the bottom of the bucket and reduce the circulation of dirt back into the tankless.

Edit: Make sure you have isolation valves on your tankless before you proceed, also clean out the filter. Search Google for what both look like.
Last edited by bubuski on May 8th, 2017 10:48 am, edited 1 time in total.
[OP]
Deal Fanatic
Jun 7, 2005
8414 posts
556 upvotes
Thanks for all the information. So, I guess if I can fasten my existing pump to the 3/4" hose, it would be fine, right ? The GPM doesn't have to be specific as long as the water can flow inside, am I correct ?


bubuski wrote: Home depot, Lowes and Amazon all have utility pumps. You only need the pump to circulate the descaling liquid so your fountain pump should work fine if you can fasten a 3/4" hose.

I use the Everbilt 1/6HP submersible pump sold at homedepot, it's rated at 28GPM so more than enough flow. You also need a 5 gallon bucket and a washer hose kit. I also use a grid guard (http://www.canadiantire.ca/en/pdp/maxim ... 1379p.html) to keep the pump off the bottom of the bucket and reduce the circulation of dirt back into the tankless.

Edit: Make sure you have isolation valves on your tankless before you proceed. Google for what it looks like.
[OP]
Deal Fanatic
Jun 7, 2005
8414 posts
556 upvotes
bubuski wrote: Make sure you have isolation valves on your tankless before you proceed, also clean out the filter. Search Google for what both look like.
I will take a photo when I am home to confirm if my system has isolation valves. I think the installer did prepare us to flush the system annually as he did mention he was going to show me when he is done installing. We just totally forgot afterwards as we got sidetracked by something........ And too bad I can't find his contact any more. By the way, it was a group buy here in RDF, I think the installer name is Brian.
Deal Addict
May 23, 2009
2274 posts
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Mississauga
rdx wrote: Thanks for all the information. So, I guess if I can fasten my existing pump to the 3/4" hose, it would be fine, right ? The GPM doesn't have to be specific as long as the water can flow inside, am I correct ?
How many GPM/GPH is your pump?

The RYDLYME kit and a few on amazon have pretty small pumps. It's just less thas than 6PGM which is within the range of some fountain pumps. I'll say aim for 10GPM but not lower than 5.8GPM.
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May 24, 2008
3215 posts
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Toronto
rdx wrote: I will take a photo when I am home to confirm if my system has isolation valves. I think the installer did prepare us to flush the system annually as he did mention he was going to show me when he is done installing. We just totally forgot afterwards as we got sidetracked by something........ And too bad I can't find his contact any more. By the way, it was a group buy here in RDF, I think the installer name is Brian.
If it was Brian through an RFD group buy you were dealing with Stouffville Home and Comfort. They are now called Comfort Masters. They would definitely have installed bypass valves for flushing. I assume it's a Rinnai unit?

Now, I have some recent experience with flushing and it's not all good. Last Friday I did the flush on our Rinnai RU98. When I was ready to turn everything back on again, the hot water shut off valve broke. The handle on the valve literally broke clean off - completely corroded. Water spraying everywhere, but luckily the inlet valve was still fine so I could just turn the water supply off. I called Comfort Masters and they had a crew nearby that could come over on short notice and take care of it. What a mess, though, and I wonder what can be done to prevent the valve from corroding? Looked around online and I couldn't find this to be a common problem. Maybe I just got a bad valve.
4 years of pain for Ontario...
[OP]
Deal Fanatic
Jun 7, 2005
8414 posts
556 upvotes
Ok, good to know. Will go home and check.

bubuski wrote: How many GPM/GPH is your pump?

The RYDLYME kit and a few on amazon have pretty small pumps. It's just less thas than 6PGM which is within the range of some fountain pumps. I'll say aim for 10GPM but not lower than 5.8GPM.
Deal Fanatic
Mar 10, 2004
6174 posts
2287 upvotes
I use one of the cheapo drill driven water pumps + 1 plastic 5 gal pail and 3 old washing machine fill hoses.
https://www.homedepot.ca/en/home/p.dril ... 21575.html

Be prepared to get no more than 2 flushes out of the pump before it dies (it's only $12 so no great loss) + make sure it is well primed as it uses the liquid it is pumping to cool the bearing.
[OP]
Deal Fanatic
Jun 7, 2005
8414 posts
556 upvotes
Yes, it was the RFD group buy like 5-6 years ago, and I think my unit is Rinnai 75 (need to double check when I am home).

Sorry to hear you have problem with the valve. Hopefully, mine is ok......... By the way, did they charge you to fix the valve handle. I wonder if they are not around at that time, would they come to fix it.
Little Tim wrote: If it was Brian through an RFD group buy you were dealing with Stouffville Home and Comfort. They are now called Comfort Masters. They would definitely have installed bypass valves for flushing. I assume it's a Rinnai unit?

Now, I have some recent experience with flushing and it's not all good. Last Friday I did the flush on our Rinnai RU98. When I was ready to turn everything back on again, the hot water shut off valve broke. The handle on the valve literally broke clean off - completely corroded. Water spraying everywhere, but luckily the inlet valve was still fine so I could just turn the water supply off. I called Comfort Masters and they had a crew nearby that could come over on short notice and take care of it. What a mess, though, and I wonder what can be done to prevent the valve from corroding? Looked around online and I couldn't find this to be a common problem. Maybe I just got a bad valve.
[OP]
Deal Fanatic
Jun 7, 2005
8414 posts
556 upvotes
Thanks. Good to find a $12 pump. By the way, how come it expects it won't last two flushes ?
plymouthhater wrote: I use one of the cheapo drill driven water pumps + 1 plastic 5 gal pail and 3 old washing machine fill hoses.
https://www.homedepot.ca/en/home/p.dril ... 21575.html

Be prepared to get no more than 2 flushes out of the pump before it dies (it's only $12 so no great loss) + make sure it is well primed as it uses the liquid it is pumping to cool the bearing.
Member
Apr 30, 2004
270 posts
76 upvotes
I have Rinnai- valves come with a unit- so probaly you have them in place.
Bought a $50 pump that is drainig water from a pool cover- doesn't work, not enough pressure to pump vinegar thru Rinnai. Nothing is coming out, pump is working.
So got a $100 utility pump from HD works good.
But it start making noise and some black powder coming out after 30min running it. Must be vinegar dissloving a pump too.
In the end- it did the job.
Sr. Member
Mar 19, 2013
696 posts
207 upvotes
Prince Albert, Sask.
rdx wrote: This is the pump I have : Resun SP 1800. It says 1000 litres per hour. Good enough ?

http://www.reefdelivered.com.au/product ... %7Dph.html
It will be fine. You are circulating vinegar, it does the cleaning. If the pump can do that, good. HP/litres per hour is not important. I bought the cheapest pump I could find.
What was important, pump had the ability to connect "washer" type hoses. Isolation valves on the tankless are a must. As for how to do it, lots of very good videos on the web.

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