Radiant Heat. Should I raise the temp?

HomerJSmith · December 11

Doesn't the Nobel have a factory installed boiler pump in the boiler cabinet?

hot_rod · December 11

https://forum.heatinghelp.com/discussion/comment/1876606#Comment_1876606

The Nobel combi has a pump, I believe, the Knights come with a pump, I don’t think the heat only Nobel comes with a pump?

The indirect look like it has a smaller pump, an 007 maybe?

So if the boiler is happy, and not kicking out on limit, then the same pump should work on the boiler loop

For the heat only version they provide the pressure drop and pump selections making me think the pump is installer provided. A 007 is adequate for the two smaller sizes

If that is a 150 it looks like an 0011 or 0013 is the recommended circ

bjohnhy · December 11

I agree with hot rod on "This just isn't the correct way to pipe it no matter how many ways you look…"

However, since there are only two 2ndary circulators (indirect DHW circ and the radiant loop circulator) re-piping the tight H connection (into typical closely spaced Tees) will probably have no significant change on function or efficiency, IMHO. If there are future plans for additional secondary loops, such as a hydronic coil for the air handler, it would be wise to repipe the tight H as outlined by hotrod.

https://forum.heatinghelp.com/discussion/comment/1876601#Comment_1876601

buildhouse · December 16

Main loop pump is a 0013-F3-1IFC

Secondary pump is a Taco 007-F5

Boiler is NKB150N

We turned off the main pump manually and ran the secondary pump to see if has any effect on the flow through the hydronic loops. It did not. So it seems that are adequately separated and that's not creating the issue.

hot_rod · December 17

That is the correct circulator for that boiler. The 007 may be a tad small with all those loops

. As expected, that H will, does, allow adequate flow to the boiler. But without the proper tee spacing, possibly the 007 cannot get adequate flow.

Interesting that what looks to be a 007 on the indirect flows enough gpm through the boiler. Typically the indirect pump would be sized to the boiler spec, the 0013 when piped parallel like that

When heat output is too low, the options are increase flow, or increase SWT.

JohnNY · December 17

I haven't read through these replies but I thought it might be helpful to know that for the 15 months of my 56 years on earth I owned a house which I sold 7 months ago. In it, I installed radiant floor heating in a couple bathrooms and a hydronic towel warmer. I used the same Lochinvar Noble boiler you've got there, I think, but mine was a combi. When it ran for RFH it short cycled and drove me nuts. When I finally installed a buffer tank, the whole system worked beautifully. I found in my shop a 20-gallon indirect water heater and used it as a heat exchanger to keep my floor water at around 130° without a mixing device. Instead of the floor becoming my heating load, my indirect with a long adjustable-differential aquastat became my load. The cycles ran longer and less frequently and the cold spots on the floor disappeared. What a difference. At great risk, I'm posting a picture of my setup here. There's plenty to criticize about the installation but whatever. It was my house using repurposed parts and shortcuts I knew I could get away with.

Radiant Heat. Should I raise the temp?

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