Did it just start doing this out of nowhere? Did you make any changes to the system? It sounds like one possibility is that the coil is leaking and the shutoff valve to the coil isn't full closing. Are you sure both inlet and outlet to the coil are not getting any house water to them?

only have one valve to coil (cold going in)it started a few weeks ago plumber came out drained expansion tank said that should do it was fine for about 8 hrs wasnt that cold out and boiler did not cycle that long.also after running and cooling down you need to add make up water sometimes more than once after between cycles but there is no visible leaks anywhere or water stains around radiators or pipes or boiler. sometimes pressure will go down to about 3# after cooling for a few hours.

You'll have to isolate the coil on the hot side too. You can always have a single lever faucet (Moen) that is leaking through and putting house pressure on the outlet of the coil. It's also possible to lose boiler water at a leak beneath the jacket and the water evaporates before it hits the floor.

I can't seem to make the connection between the increase in pressure and the loss of pressure and the makeup water necessity. Maybe somebody else can.

would it make a differance if i shut off main water supply or should i try to cut the hot line and put in a shut off valve? also would it be possible for the expansion tank to be bad without leaking i feel like the expansion tank should be taking on more water at the pressure it is building up to the tank is an old one 1960's-70's and is adout 60"long by 11" in diameter.

The only problem with a tank that I know of is that they eventually fill with water. Shutting off the water to the house to do a test is easier than putting in a valve and would accomplish the same thing, but first relieve the pressure in the water lines. Alot of people like their ceiling hung tanks. I've had my Fill-trol tank for 30 years and never had a problem with it. I am wondering about your problem with water loss.

have to give that a try tomorrow like i said i would have thought the expansion tank would take on a good bit of water as the pressure builds up but even as the relief valve starts to open the tank does not seem to be taking on water. tank cold not warm and still hollow sounding.found 1 small leak at front of coil housing but it is only about 1 small drip in about 45 minutes

what is the brand name of your boiler? Try to tighten the coil plate nut to stop the leak. It will eventually rust the steel under the gasket and ruin the seal.

trianco

I asked about this with our salesman, who has 50 years of experience in this field. He can't count the number of times that homeowners say the expansion tank is empty when it is not. Knocking on it won't tell.

When you open the valve, some water will come out and then it vacuum locks. He said the way he would solve this problem, and you need a bucket handy because the water will come pouring out, is to shut down the entire boiler operation, close off the valve from the boiler to the tank, wait until the water in the expansion tank is COLD and open the drain valve to relieve the pressure. At this point you'll need to call in an experienced technician to do the rest of the job. Don't even think of doing this yourself. The technician will remove the drain valve of the expansion tank, insert a piece of 1/4" copper tubing bent into an L shape and insert the tube into the tank so that the tube goes to the top of the tank. This will break the vacuum and air will be fed through the tube to the top of the tank and the cold water will come flowing out.

thanks have a tech coming out tonight or tommorow to look at it i think i figured out were water is going my daughter said she hears a whistling sound a couple times at night the relief valve i guess each time it opens during the night it dumps enough water out to require make up water i will show this to tech but the tank never seems to get warm. thanks for your help ken

A Trianco Heat Maker is not like your typical boiler and only people experienced with them should even take off the cover. The best thing to do get professional help. Firing these boilers dry for even 2 seconds will ruin them.

ok tech here today seems to think the problem is being caused by the boiler being undersized says make up water is needed because of blow off at releif valve does this sound right to you guys?

If the boiler was undersized you would have been having this problem since it was installed. Has the hot water usage increased greatly? Blow off at the relief valve will cause make-up water to come in. It's not good for the boiler to have fresh water added, so I would solve the blow-off problem right away.

I'd call the company back and ask them to send someone over who knows what the hell he's doing. The relief valve is a safety device and your's is blowing off. Oversized, undersized, or anywhere in between, it shouldn't matter. That's the systems way of telling you something is wrong and needs to be corrected. And here you have some Dink telling you water needs to be added. OH REALLY??? I think you know that already! Find a company that has experience servicing Trianco Heat Makers.

i noticed the problem as it got colder and the heater needed to run longer periods of time. the water was added after blow off when it cooled for a few hours. his explanation is with it being undersized it is running longer than it should because of large amount of cold water in whole system and by the time it finnaly heats up it is building up excess pressure and that i may have not noticed it before it got real cold and had to run longer average run time to go from 62 degrees to 64 is about 1.75 to 2 hours.he checked over and did some checking said he would check on a few things for me and get back to me in a day or two. no charge for the service call today anyway.

After the expansion tank was drained was the valve between the boiler and the expansion tank opened again?

your system, with the properly connected and piped/valved expansion tank, should be able to run for eternity or until it runs out of fuel, without blowing off.

there is no shut off valve between tank and boiler. i guess whoever paid for the install went the cheapest way possible have been finding this out for everything in the house.

ok did not here back from repair company so i bled the system down a good bit added water to the boiler 15# cold pressure did this 2 days ago now after running for about an hour pressure hits about 20# and has not needed any make up water added . i will keep fingers crossed but would still like to find out what was going on.