Baseboard not very hot

Old 03-01-19, 08:55 PM
Thread Starter
Join Date: Mar 2019
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Baseboard not very hot

Hi all,

I had my natural gas boiler replaced last year and have since feel like the baseboards are not getting hot. The system is quite, psi about 20lbs and heating to 170. House is 2 zones about 1100 square feet per zone. I have electric 2 zone control valves and one Tyco variable speed pump at the send side. Also have a blend bypass. While I feel heat through the house and we get up to temp I feel like the system is constantly running and pipes at both sides of the baseboard are hot but not 170. Can grab and hold hand there. My questions before I get a plumber in to look:

1. Is one circulator pump enough for that size?
2. If so, should I be running it on slow, medium, high? Currently its medium. Is there one route that would make the pipes run hotter?
3. Should the blend/bypass be wide open or somewhere in between?
4. Finally, if you run from the unit is hot, could it be a block?

thank you
Old 03-02-19, 04:31 AM
Join Date: Oct 2008
Location: USA
Posts: 2,605
Received 28 Upvotes on 27 Posts
First, you should call back the installer and let him solve the problem.

Otherwise, jack up the aquastat to 180 deg. Also, throttle back the bypass a bit. But once you start messing with settings, your installer may blame you.
Old 03-02-19, 10:35 AM
Join Date: Oct 2013
Location: United States
Posts: 2,768
Received 141 Upvotes on 133 Posts
Did you have this problem with the old boiler and did he change the way the system is piped in any way. A lot depends on the system design. If you have a series loop system where the baseboard is part of the loop and not individually fed off of it then you must see how much baseboard is being heated before the water returns.

Check the difference in temp from the first piece of baseboard to the last. Every piece of baseboard that is fed is going to lower the temp of the water. If you can hold your hand on the pipe at the end of the run you most likely have too much baseboard on that loop. Pipe size also plays a part. Each pipe size can handle a certain amount of BTU's. For example a 3/4" copper pipe can handle up to 45,000 BTU's. See how much baseboard element is on the loop. Each foot puts out about 600 BTU's a foot with 180 deg water going through it. Less than that with cooler water. As gil mentioned I would raise the boiler temp to at least 180 to get the amount of heat the baseboard is rated for and if this just happened after the new install call the installer back and get his take on the situation.

Pics or the boiler and piping would be helpful if possible.

Hope this helps a little.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: