Hot water heater not working after boiler was cleaned

hiaku112

I had my boiler cleaned 2 weeks ago by a professional contractor and afterwards the hot water heater isn’t working. It’s an indirect hot water heater that is heated with the water from the boiler. I had the contractor back but he can’t figure it out. I put a new circulator pump on, flushed the system out thoroughly multiple times. I can get hot water if I open the flow check valve manually, which is a taco 218, so I know that isn’t stuck. But the circulator pump never shuts off. Any ideas on what could be the problem. Oh yeah, the hot water heater is 9 years old and we had the boiler cleaned every year without any issues.

Ironman

It could be air bound. Is the circulator pumping in the right direction?

Some pictures might help.

hiaku112

yes the circulator pump is going in the right direction. But circulator pump is on top of the system and I think that may be part of the problem, but we never had an issue with it before.

hiaku112

Here is another picture showing the complete system. Pipe coming from the boiler goes into the check valve and then the circulator pump. I turned the pump with the motor on top thinking that might help.

EBEBRATT-Ed

Open the flow check valve set the indirect to call for hot water and leave the boiler off. Let the pump run a while as long as it is pumping. That should move any air back to the boiler. You should have an air vent or air eliminator on the boiler.

Ironman

That’s a bad setup with the flow check on the suction side of the pump. It should also be mounted with the motor horizontal, not vertical.

EBEBRATT-Ed

Why two different model pumps? which picture is the before and which is the after? @Ironman comments about the pump mounting and the flow check are spot on.

Alan (California Radiant) Forbes

If you get hot water when you manually open the flow check, leave it open. You probably won’t get gravity flow with your system, so you may not need that flow check.

hiaku112

the second picture is how it was when the boiler was cleaned and the first picture is what I tried thinking it may get the air out

tim smith

Have you purged it at the hose bib there on return at bottom with the ball valve next to it shut. That at least will flush any air out. Use fill bypass to keep pressure up but not over pressure. It may be a seized pump or broken impellar on pump if it doesnt work after flushing. Are you sure pump is running ( i.e. spinning)?

DanielDAY

I would leave the flow check wide open. What’s the thermostat set to in your tank? What is supposed to tell your pump to turn off? If it’s the thermostat on the tank, maybe lower the temperature if it’s too high but not too low obviously.

Could be coincidence but why after he cleaned your boiler would things stop working? What did your boiler guy touch while he was doing the job. If it was just a heat exchanger cleaning there’s no reason why he would have had to mess with any pipes

mattmia2

the circulator is kind of pushing any air down in to the tank coil. it would purge better to a drain up by the circulator. with the system off you can try turning off the ball valve next to the circulator and cracking open the pump flanges just enough to let a little water and air out and see if that fixes the problem.

edit: i thought the valve was before the circulator. looking now it is after the circulator so you'd have to do it with that valve open and be very careful.

hiaku112

got it fixed, turns out the new circulator was working so I put another one on and flushed the system with 22 psi for about 10 minutes and that did the trick. Thanks for all the help.