Hi,
I bought a new used house recently and it has a Weil McLane (I think I spelled that wrong) Gold natural gas boiler with Honeywell zone valves. The boiler is only about 2 years old, but can’t seem to keep up when the weather is below zero outside. I opened up the zone valves manually and left them that way. Both the upstairs and downstairs loops are hot to the touch. My pressure is steady at @32 p.s.i. and the boiler fires to 180 degrees then shuts off. There is a temperature setting inside the boiler called the water temperature limit switch that was set at 180. Where the heated water comes out of the top before it separates into two zones there is another thermostat device set at 200. Can I adjust either of these two devices higher to get more heat out of the boiler? I can hear the pump working when I use a wood dowel as a stethoscope. The main problem I think is that my loops are too long and inefficient. I have added insulation, wrapped pipes, and sealed old windows with heat shrink plastic.
Help!
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story

The LG Inverter Heat Pump Water Heater uses advanced inverter technology to ramp up or down in response to hot water demand, maximizing energy savings.
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
You need to make sure you have enough baseboard in each room your heating. Also check the input BTU rating your boiler. A normal sized 3 bedroom house (1800 to 2200 square feet) uses about 100,000 BTU Boiler. Also if you have heat loss due to infiltration (leaky windows, doors, windows, etc.) you will not be able to keep up with any boiler. If you suspect leakage then have a BPI certified contractor do a blower door test on your house and you will then find ALL your leaks.
If your boiler is shutting off then the heat output from the baseboard is not enough to compensate for the heat loss from the house. 180 should be plenty hot enough.
More baseboard "heat loss" or more insulation to slow the room "heat loss" is the way to go. Check to see if there is a bypass on the boiler to temper the water temperature. Can you measure the temp of the baseboard pipes as they enter the rooms and exit?
Where are you located ,you really need to have someone look at your setup.
What is the pressure setting of the relief valve? Most are 30 psi. 15 should be lots.
Might be time to have a good boiler tech take a look.
You probably have fin tube radiators?? Make sure the fins aren't all clogged up with dust etc. You should vacuum every one of them, and make sure the furniture is not blocking air flow through the baseboard units. Make sure all the flappers are opened wide on the radiators.
and then start air sealing and insulating!