replaced all parts still has over 30psi burnham V8 boiler

Jamie Hall

Agreed. And my reaction is possibly more firm: the first place I'd look would be for the expansion tank to be undersized, or improperly precharged (either too much precharge pressure or too little could give you the symptom of excess pressure change).

RickeyB

the system has operated for 20 years after installation. I Don't remember exactually when this issue started as i mainly heat with wood. For years I traveled for my job and my wife used the furnace to heat and used no wood.

Using only the domestic hot water it stays around 20 psi ,I tried the baseboard heat and saw it climbed up to 29 on first fill and shut it down by turning down thermostat. the pressure dropped back to around 20psi.

I started to check the HWC by what the tech's had stated in my post. shut off water to coil, shut off system power, removed water to get to 15psi. 30 min wait ..and it reduced the pressure to about 5psi. The instructions say that if it rises it could be the HWC but nothing about if it lowers.

so for the expansion tank being under sized , wouldn"t that have been an issue from day 1 and not 15 years latter.

my house is small and the tech who did the shotgunning said that my unit was overkill for the size of the house .

I guess I will have to find another burner tech and take my chances

EdTheHeaterMan

If your water pressure drops to 5 PSI that means the expansion tank may be 3/4 full of water at 12 PSI. When the water in the system cools and the pressure drops to something lower that the 12 PSI air pressure that is supposed to be in the tank, then you should get a tire gauge and see how much air pressure is in that tank.

As far as the boiler being oversized, that is possible, but it should still have 12 PSI on the boiler gauge, when the system is at 60° to 70° water in it, have the auto feed valve set at 12 PSI and have 12 PSI air pressure in the tank when there is no water in the tank.

After the boiler gets hot and all the radiators get hot, the pressure should not go above 25 PSI and really should stay around 18 to 20 PSI.

RickeyB

let me start again as to what i did.

I read thru the information from last Jan. To again figure out the cause of a rising pressure when the boiler is running. Just a normal small house with a burnham V84 hot water tankless boiler feeding baseboard. 20 years old. Reading thru the info given there are only 3 reasons for this to happen.

1. Expansion tank has gone bad or no pressure in it [ just measured it this morning and see 15 psi ]
2. PRV pressure reducing valve . The last tech changed it and then I changed it with no change in raising pressure
3. Boiler hat water coil
   
4. Test was to shut off water to coil, remove water to get around 15psi.shut off system and watch to see if pressure goes up for 30 min. Pressure dropped to about 5 psi. What does this mean if anything ?
   turned water to coil back on and pressure went up to around 12 psi

what next ?

RickeyB

my bad on spelling. Rising not raising

RickeyB

Ok , I called my fuel oil dealer and asked to speak to the tech that they use and he works for the oil company. A large company with lots of gas stations and they bought the local oil dealer. Told him my problem and he stated ( funny he lives a couple of miles from me ) his boiler runs around 30psi and that is not a problem. I'm afraid to run the boiler and have the 30psi PRV valve open. asked for the cost to replace the HWC hot water coil and he said $2000. how much for the boiler replacement about $10000. WOW So he said to call the last tech that took me for a lot of money. Real good customer service . I guess i don't have a choice and run it and see if the PRV pops open. I worked for years as a field tech on million dollar machine troubleshooting and would never shot gun a problem. WE had techs who would tell customers to order all kinds of parts and would they would not fix anything and the company would not take the parts back. have a great day all

RickeyB

if the PRV relief 30 psi valve blow open does it need to be replaced ?

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1835570#Comment_1835570

Not necessarily. If the valve reseals than it is still good.

Not a fan of the oil company you are using, I would look for a new one that has better customer service.

Where are you located?