At my wits end!!!

mikerulu

Long story short. I bought a home 1.5 years ago in Seattle the home has a radiant floor heating system with radiant base boards in the day light basement. It is hooked up to a Cosmos Gas Axia Boiler running on Propane. I've had the boiler recently serviced (about 6 months ago). Now here's the problem: every day it is tripping the "low pressure" shut off valve and shutting the whole system down, floor heat stops and the domestic hot water stops. If I'm at work and don't catch it in time the radiant floors go cold and it takes a while to get them heated back up. Since it is now a daily occurrence I'm having to manually start the boiler daily by manually filling it. Since it takes awhile to get the floors heated up I'm also going through Propane like its free. 155 gallons in 4 weeks! Any ideas why/what is going on? Mind you the floor system isn't losing pressure it's the actual boiler. First photo is it up and running with good pressure and the floors on. The bottom photo is it at fault and no pressure red alarm on.

kcopp

I bet this is a water quality issue. That unit has a pressure sensor in it and is probably getting fouled.
You need to clean the water side of the system.
Flush the system w / new water.
Add a cleaner to the system... Fernox, sentinel, Rhomar. let it run in there for a week.
Flush out all that crap that will be cleaned off the inside of the system.
Then add an inhibitor.

Are you sure there are no leaks?

Paul48

@kcopp
I'll take that wager! LOL
The gauge reads "0". I thought the same as you, until I saw the gauge.

kcopp

How is the tubing installed? I have seen situations where nails have penetrated the tubing and had a small leak that show up over time.

Harvey Ramer

A leak would also explain the boiler's appetite for propane.

Gordy

As been said verify that none of the radiant loops have a leak. Isolate each one.

You are going through propane because your radiant floors are not getting to a steady state condition. Approximately 5 gal per day. However you are heating domestic also. Total equates to roughly 18000 btus per hour avg. after a 10% efficiency hit. Don't know anything about structure, or degree days for the month.

Gordy

If you have tested the loops, and are adiment that there is not a leak then there must be a whole lot of air in the system working its way out. However I do not see an active air removal device in place.

mikerulu

@gordy there is a bleed air valve at the top of the unit. I will double check that to make sure it is working properly.
@Hatterasguy I guess I came to that conclusion because when I manually start the boiler the water in the lines seem to be fully charged I don't hear water move when it kicks on.
@kcopp my flow meters on each of the lines have the same amount of flow through them. If there was a leak would any one of them read differently? I have no visible water marks on the ceiling from the basement side. I also just checked the baseboards and all are dry. Any other way to check?

Gordy

What type of radiant? Concrete, gypcrete, staple up,over the top sleeper?

A leak can still leave the loops filled with water. One way to tell is your make up water normally on, or off. I will presume off since you lose pressure.

mikerulu

@Gordy From what the previous owner told me they remodeled the basement and as they were they installed the tubing in the ceiling. So....I guess staple up.

Gordy

Okay so the basement has radiant ceilings, or the main floor has staple up? Tubing installed between the floor joists to heat the floor.

JUGHNE

You could perhaps narrow which manifold has the leaker if one, Just shut off the ball valve for one side and be sure the zone valve doesn't open. Run the other for a couple days.
Then reverse the process for the other manifold.

Then do each circuit separately once you know which manifold it is connected to.

mikerulu

Basement has the baseboards. Tubing running in between the floors of the upper and ceiling of the basement. I'm assuming they have it installed between the floor joists.

kcopp

Can you add water to the system? What does the gauge do? It could possibly be broken...

kcopp

The expansion tank is in the boiler. The Axia units have a Zilmet tank inside to the side.

kcopp

Hatterasguy said:

kcopp said:

The expansion tank is in the boiler. The Axia units have a Zilmet tank inside to the side.

What is the possibility that the tank is completely full?

Depending on the age of the boiler.... not unlikely. But the PRV would be leaking.

JUGHNE

Can you see the end of the drain pipe connected to the pressure relief valve? Have you ever seen it dribble water?

Gordy

If the X tank were full there would be no room for expansion in the system. There for the relief valve would pop to relieve excess system pressure when heated. Unless this has just started to happen, and we are still filling the X tank. However it is small, and would not take much to fill.

bennyboy

I had a similar problem much like your but had a variable pressure water feeder "cover up" the problem.
But I induced the problem some months ago and the problem did not manifest until the weather got cold and I adjusted the DHW to a higher temperature on my condensing and DHW boiler.
The culprit was the temperature pressure relief valve which did its job to reduce pressure when the DHW side reached 30 PSI upon a maintenance DHW call.
So every day, I came home to closed loop water in my bucket where the relief valve dumped into from indirectly heating my water to 140F.
The culprit was as result of me changing the internal boiler pump from medium speed to low speed to save a few watts of power during boiler or DHW run time. The other side of the close loop where I have radiator and pex in ground emitters never caused the relief valve to even move from 10 PSI. But the other side of the close loop where a three valve decides (either CH or DWH call) didn't have capacity or an expansion tank or the flow rate to remove the modulating flame hence causing the relief valve to open.
Yes, I even replaced the TP relief valve with no luck until I deduced my problem and reverted the pump back to a medium speed per factory setting and now all is good again.

If you aren't having leaks in the system, watch the pressure go up during either call for heat or call for DHW and look for signs of water discharge via that TP valve.
From the looks of your picture.. it dumps south of the boiler into ?.
Sometimes these valves go bad.
and get a water filler and expansion tank too.
and lastly check the speed of the pump.

good luck

happydave

Is the vessel itself leaking? Bump up the pressure and put the condensate drain into a bucket without the boiler running and wait a hour( if it is a condensing boiler) or does it sound funny when it first restarts- extra steam in the exhaust?

mikerulu

Everytime I add water to the system to get it restarted the pressure relief valve dribbles water. In fact I have a bucket under their now because I have to restart it every day. There aren't any visible leaks in the system that I can see. I don't see any water stains or marks on the boiler itself.

added a video off the system running.

https://www.youtube.com/watch?v=EpLPc-lU6ok

mikerulu

Whats a good source to find a new tank?

kcopp

http://www.houseneeds.com/repair-parts/mestek-embassy-ambassador-axia-gas-boiler-axia-repair-parts

mikerulu

Looks like there are no tanks.

kcopp

did you scroll down?

Zman

You might also consider the sizing of the tank.
The 2 disadvantages of on board tanks is availability of parts and correct sizing. Tanks should be sized to the system which will be different in every application.
I guess if it worked before it should work again. Not sure quite how that one is connected but it looks like you have room for generic tank below your boiler. The tank would be about a third the cost. You would have some additional parts and labor to make the changeover.

mikerulu

Ok I'm confused now. @Hatterasguy said the internal tank has failed. Your saying I can replace the internal tank with a separate one? Also @kcopp I don't see any internal tanks listed on that website only replacement expansion tanks.

Paul48

That's because Sherman tanks won't fit internally. (internal expansion tank)

Gordy

When "internal tank" is used internal we refer to inside the boiler the red expansion tank.

kcopp

This is the exact replacement.... I have replaced many.

http://www.houseneeds.com/repair-parts/mestek-embassy-ambassador-expansion-tank-axia-bms-part-62202001

mikerulu

Gotcha Thanks!!