Nti boiler too much psi

Sfam

We removed our combo boiler nti to just use as a tankless for hot water. We went forced air. We removed all components from the steam heat. We have a ton of discharge from the purge valve which the psi is sitting around 20-30. How do we lower the psi on it 

dko

edit: I may be wrong

Can you post your NTI model number

Jamie Hall

Yes please. We need the model number. And I'm confused. This is the very first time I've encountered a combi being used for steam heat. Something just does not compute here.

pecmsg

Sounds like a Heat Pump replaced everything.

Sad very sad!

WMno57

Sfam said:

We removed all components from the steam heat.

I wonder if they removed the expansion tank?

GGross

can you take a picture of the install as well

Mad Dog_2

He probably meant "system" heat..Mad Dog

Sfam

Sfam

I don’t have a before pick still looking. For one. We used to have baseboard heat all around the house. We removed it all and closed everything up

Sfam

thanks everyone

Mustangman

Im a little confused. Did you just abandon the heating side of the boiler and just are using the combi part of the boiler? If the boiler pressure is going up, you may have a bad plate heat exchanger. If it has a tiny hole, you are putting city water pressure in the boiler. Boiler pressure is much lower than city or well water so naturally the boiler pressur will rise… remember at 30 psi, the relief will dump. I assume that you checked and set the boiler pressure with the PRV? We get so many calls for boiler relief leaks or high boiler pressure. I tell the men its always one of 3 things. Bad fill valve that is over filling, water logged expansion tank, or bad relief from people yanking on the relief lever everytime they walk by it. Hope that helps.

GGross

You still need an expansion tank on the heating side of the boiler, looks like you put one on the domestic piping, but that tank never sees the boiler water.

You need 2 relief valves total (one for DHW, and one for boiler), and at least an expansion tank on the boiler side, preferred to have one on the DHW side as well but not always necessary

you need these things whether or not you are using the boiler for space heating, it is still a pressure vessel, and it is still being used to heat your water, both the DHW and boiler side are used to make DHW

It's a good thing these boilers have built in safeties

Jamie Hall

And I hope that you didn't drain the heating side of the system. I the heating side heat exchanger is dry, it will die a nasty and early death — if it hasn't already. Not sure quite how I would handle that situation, since the heat exchanger must have water in it — and that water must take the heat away from it, even when only the domestic side is calling.

hmm…