boiler pressure issues ?

clammy

I have a friend who has been having  service issue with a crown oil fired direct vent hot water boiler ,he runs a oil company .They have been having a safety valve weeping on the boiler .They have replaced the feeder ,expansion tank ,trindiator and the aquastat control being the boiler was over shooting the hi limit setting.The boiler also services a indirect water heater,they have isolated the city water line and also isolated the hot and cold water lines to the tank and even so after 5 to 7 days the boilers safety is weeping again .The boiler has 1 pump mounted on the return and they are using honeywell zone valves mounted on the return  .The boiler and system was installed about 7 years ago(by others) and this issue has just started very recently ,some one did add a radint zone for a addition about 5 years ago and that also has been isolated yet after  a week or so the safety starts to weep again.I suggested to look at the pump and temperture difference across the indirect loop and see if there is a increase in the boilers pressure when this is the only zone calling fiquring that maybe the boiler is being pressurized by the pump during a call for hot water,i also suggested to pull the zone valve apart to check for any rap blocking the port which may restrict flow to the tank causing a increase in pressure with in the boiler.They did isolate the indirect and pressurize it with 150 psi and found no inrease in the boiler pressure nor a drop in the tank side which they pressurized whih in other words leads them to believe that the tanks domesti side is not leaking intot he boiler side and causing the valve to weep .Also the safety valve is sized properly for the sysytem as is the expansion tank .For the weekend that have isolated the radiant loop and still have the boiler make up  ball valve closed i did suggest for them to check and be sure that the valve is working properly and not leaking water into the system whih they assured me was not happening .I also advised them to make sure no one has been knuckleheading the system with out them knowing (tying into a heat loop by mistake thinking it was awater line )I have not looked at this yet and may take a peek next week if it an not be resolved by there servie tehs but am still looking for any one who has seen this and may have soem input .Peace and good luck clammy

icesailor

leaks:

If the boiler/low temperature is isolated from the domestic heating system, and you disconnect or turn off the fill to the heat system, there is no way on earth that the system can rise up to 30#. It just can't. If you have a high pressure source connected to the heat system (12#) and you have 60# on the other side, the indirect, it can't come from any other place. They didn't test the indirect properly.

"I" would valve off the domestic hot water coming out of the tank, disconnect the indirect coil from the heating system, and connect my air compressor to the (1) indirect piping from the boiler and pump 100# and wait for the bubbles. Doing this will need a pressure gauge on the indirect tank to look for the rise in pressure. Or (2), pressurize the indirect with 100# of air and watch the water come out of the tank.

If it is a SuperStor, it may be leaking through the flared fittings that send the indirect water into the coil. Either way, I think that the indirect is burnt toast. Everything else you have mentioned is just a distraction.

Jean-David Beyer

A W-M indirect would not like that.

"connect my air compressor to the (1) indirect piping from the boiler and pump 100# and wait for the bubbles."



Maximum presssure in the outer tank of a W-M indirect (an almost certainly a T-T as well) is 45 psi. And this only if the inner (domestic) tank is already filled. My guess is that exceeding this would collapse the inner tank. But if the inner tank is leaking, the problem might go away by cutting off the supply to the indirect. With something like a W-M indirect, you could probably, cut off the supply and return from the boiler, remove the vent at the top and put a pressure gauge there, and await developments.

icesailor

W-M Indirect

You are absolutely correct. I have a few houses I drain for the cold months that have them. Fortunately, these houses leave the heat on but I drain the water. I can leave the tanks as they are. If I had to drain them, to drain them, I must drain the outer tank first, then drain the inner tank. To return them to service, I must fill  the inside tank first and then the outside tank so the inner tank doesn't float. It's also why I have never installed one. Then, there's the special Massachusetts requirement for the second dip tube so you can drain it. Which not many seem to install. I found the dip tube in a closet once. A good place for it. The instructions are vague on this and besides, few like myself bother with reading those complicated instructions. They don't need to. They already know all the answers. Someday, before I die, I hope that I will know all the answers.

Did someone say that the indirect in question was a Weil-McLain? If they did, I missed it. 

billtwocase

clammy

I'm sure that if you make a site visit, you will not need any advice from us. I would like to see pics. Where is the extrol located? Any flow checks or zones added to the boiler supply? Perhaps the tank is isolated when the zone valves are closed due to something on the supply? Cold start boiler? sounds like the indirect and PRV have been ruled out? Haven't seen one in years, but thermostatic fitting on the supply? Tank sized for system? Just a few to start

Jean-David Beyer

Someday, before I die, I hope that I will know all the answers.

A bumper sticker I like:



Hire a teenager! Get them on the payroll while they still have all the answers.

Steamhead

Look for another fill line

I've seen houses where the original fill connection was way over on the other side of the basement from the boiler, teeing into a radiator run-out. In one or two cases the original fill was left in place (shut off) when a new line was run to the boiler area. If this leaks, it can cause the problem you're having. Check the entire system over to make sure there's no other way for water to enter it.

clammy

Thanks for input

Sorry as i did not word it correctly for you ice-sailor ,they did test the indirect properly and there was no drop in pressure on the portable side  nor increase on the heating side .There is some wacky radiant piping with a separate feed which is shut off and may have been used to power purge the radiant it is unknown to me i had nothing to do with it.According to the judge who's home it is nothing has been done to the heating system (other them yearly service)or the home for at least 5 years .Everything is pretty much original and there service records(oil co) show no issues with feeders, safety valves or basically any thing on the boiler ,it has been running fine for 7 years no issues and now this weeping safety .I will guess if it continues i will take a look at it when they ask .Thanks for the input and assurance peace and good luck clammy

icesailor

I still think

it is the indirect. If you physically remove the the backflow and the pressure still goes up, it can't be anywhere else unless you have another indirect connection somewhere. You can't make water pressure out of thin air. If you are leaking water from the PReliefV, that water came from somewhere. I don't think it was tested correctly. In MY world, unless I personally test it, MY WAY. I don't consider it tested. If the fill valve/PRedV is turned off and it is making water, raising the system pressure and blowing the PReliefV, it's a cross connection. Contamination between two pressures. All the extrols and zone valves won't change it.

Jamie Hall

Somewhere...

somehow, domestic water has to be getting in there.  Not much.  But it doesn't take much, given the five days you mention.  Steamhead and Icesailor are on it -- it's either the indirect, with a pinhole, or a wonky feed somewhere.



I wouldn't say that if the PRV wept only under certain circulation conditions -- for instance, I suppose that there might be a way to shut off the expansion tank at times, for some reason, which would do it.  But you'd have found that.



How would I test it?  Physically disconnect stuff.  Not just close valves, but find somewhere where I could actually physically disconnect the feeds.  And just possibly exercise a lot of patience.  All that is assuming that I didn't find another feed somewhere (I like Steamhead's idea!) which is leaking.

Mac_R

Pressure Issues

you might be going on about this the wrong way.  the first thing I would find out is there any air getting into the system.  I had a system with the same problem and finally after doing some reading (thank you Dan) I found out that the air vent above the circulator was letting air into the system and because air displaces water.  Pop goes the safety valve.  Your best bet is to install an air scoop in the supply line with a Extrol exspantion tank screwed into the bottom and a good quality air vent on top.  If you have the space reposition the circulator to pump away from the tank as well.