New Boiler acting weird

bask691979

I purchased a new Crown boiler a few months ago after my 35 year old Crown cracked above the water line. In the beginning I had some banging in the pipes, but replaced both main vents (with what ever the local plumbing supply house had) and all the radiator vents with Varivalve quick vents. The banging has gone away. My boiler with fire up when the house temp goes down runs for about 30-45 minutes and raises the house temp about 5-7 degrees. It will then shut off for about 5-10 minutes and fire up again. I have a pressure differental control with the input set at 1.5 and the diff set at about .5. My upstairs temp control is a honeywell cronotherm that was probably installed with the boiler 35 years ago. Any ideas on what is causing the boiler to fire up the second time after the home has heated up 5-7 degrees. Any help would be appreciated, thank you.

Paul S_3

who sized your boiler? EDR calculation? it may be tripping on the pressure troll...try setting differential to 1...this may help but I doubt it.......could be the thermostat...you can replace it with a standard tstat and set it for steam....Post some pics of the near boiler piping and the new boiler....could also be tripping on the low water cutoff...was the boiler skimmed?(cleaned)after the installation

bask691979

Thank you for the suggestions. I'm not sure how to post pics (new to the site). The boiler was sized by the installion company, they came in counted all the radiator segments and came up with the required size. The home is about 1500 SQFT, the boiler input is 138 with an output of 113. They put in a cleaner in after install and did skim the boiler. I have personally skimmed the boiler twice since install and the water is clear, but surges about an inch when running. Originally the water level was low, the boiler only had a minimium water level mark. After reading the install fire up instructions I adjusted the water level to the correct height and placed a mark on the boiler for reference. I just adjusted the pressure input to 1 see what happens, and I do have another upstairs thermostat that I was hoping to install once the weather got into the 70's, but might do it today.

Paul S_3

Take pictures from your phone and upload using the attach file icon that's above when your posting a new comment ....i took a picture of it below....does this boiler have an auto water feeder?

Jamie Hall

Sounds to me like a thermostat problem. Unless you are changing the thermostat setting, the boiler should shut off before raising the temperature more than a degree or two.

bask691979

lets see if this worked

bask691979

First attempt to attach photos was a fail round 2 yes there is a auto water feeder

nicholas bonham-carter

Use a jumper wire to simulate a call for heat on the thermostat wires, and see if the boiler continues to fire nonstop. If it does, it may indicate a problem with the thermostat anticipator.--NBC

bask691979

Installed new upstairs thermostat, skimmed boiler again. Seams to have changed the cycling of the boiler. It now runs for about 15 minutes and shuts off. Rasies the temp about 2 degrees. I'm assuming this is much more normal than running for 30-45 and raising the temp 5-7. I appreciate all the ideas and help. If you see anything else wrong, or can think of anything else that would make things work a little better, please let me know. Again thank you so much and enjoy the weekend.

Danny Scully

The pressuretrol is set wrong. It is subtractive, so the DIFF should be 1.5 and the MAIN should be 2.

Jason_13

A question not asked was the temp was going up 5-7 degrees. Was it going way above the setting? If so it was an anticipator change. make sure the new thermostat is set to steam on 1 cycle per hour.