Adding Panel Radiator to Baseboard Loop

[jeffesonm]

Not exactly a wood boiler question, but I know someone here will know the answer. Plus I have an EKO 40 in the basement waiting to be installed to hopefully that counts?

I am renovating a small 5x6 bathroom and bought a Runtal panel radiator to save on floor space. Right now the house is two zones, about equal length/size, all tube/fin baseboard. Burnham MPO-IQ84 oil boiler. I would really like to pipe it into the existing baseboard loop if possible. What's the best way to do that? Just plumb it in series? Or maybe put in two closely spaced T's and run it like a secondary loop?

 

[maple1]

The Ts will require another pump.

I would just series it, I think. On the end of a zone if possible.

 

[electrathon]

Series is the easiest answer. Individual room control is the only reason you would want to use T's. There are a few ways of doing it, from manual valving to automatic/thermal control, it all depends on how elaborate you want to get. Properly plumbed, t's will not need another pump.

 

[electrathon]

I just looked and it looks like those radiators are using 1/2" on their piping. That being the case, if your current hydronics are based on 3/4" piping you will need to run T's with a partially closed valve downstream of the first T to balance the water flow. Without T's you may loose flow/heat output in the entire loop.

 

[R Mannino]

You need diverter tees they are also called mono Flo tees.

https://heatinghelp.com/systems-help-center/diverter-tee-q-and-a/

 

[jeffesonm]

Thanks all. Yes the panel rad takes 1/2 and the rest of the tube/fin is 3/4. Looks like maybe I can use one standard tee and then one monoflo tee on the return as depicted in the first diagram.

Any issues if I add a TRV as well so I can adjust the temp? Based on my understanding the TRV would open/close to allow more/less heat into the room. If it closed all the way, the flow would just stop in the panel radiator loop.

 

[electrathon]

If you restrict the flow through the main loop with a diverter T's and then turn off the flow to the bathroom radiator you will restrict the flow to the rest of the loop due to the choke point in the diverter T. Depending on your house and heat loss areas it may be easier to set it manually with a valve, a little extra heat in the bathroom is usually good and you would only get that heat when the rest of the look had a call for heat.

 

[Bob Rohr]

Not exactly a wood boiler question, but I know someone here will know the answer. Plus I have an EKO 40 in the basement waiting to be installed to hopefully that counts?

I am renovating a small 5x6 bathroom and bought a Runtal panel radiator to save on floor space. Right now the house is two zones, about equal length/size, all tube/fin baseboard. Burnham MPO-IQ84 oil boiler. I would really like to pipe it into the existing baseboard loop if possible. What's the best way to do that? Just plumb it in series? Or maybe put in two closely spaced T's and run it like a secondary loop?

How many feet of baseboard on that loop? If is a short run, maybe under 20 feet of fin tube, you could maybe series the panel. 1/2" copper will move 1.5 gpm, or about 15,000 BTU/hr if you know the heat load of the fin tube rooms.

Ideally you would run a heat load for every room on that loop, size the fin tube and panel to the load, and see where you end up for GPM or required pipe size.


Use an H valve with and adjustable bypass function, on the panel radiator. This allows you to adjust how much flow goes through the panel and how much bypasses.

Typically 65% bypass, 35% into the panel, then you could also add a TRV for temperature control in the panel rad.

 

[jeffesonm]

Here is a diagram of the house and existing baseboard runs. Dark red is the baseboard and light red is the piping. I counted up all the baseboard, piping length and elbows to come up with the equivalent length calculations. Can you believe Zone 2 and Zone 3 used to be all one giant loop?!? I split these in two when I replaced my oil boiler a few years back. I did some room heat cals a while back and everything was seriously oversized for the house, enough that I could get away with running like 140-150 water in the dead of winter. I think in 1957 they just stuck baseboard on every available wall surface.




The bath in question is in the top right corner of the diagram. I am doing away with the 5' baseboard in the bath and about 15' worth of piping and the 15 elbows they used to get it up and around joists. The the panel rad will now be the opposite wall, as pictured in the next diagram. It is a small room, only 5x6. I ran some online heat calculators and tried to similarly overize the panel rad (Runtal RTR-2924) so in the future once I get the wood boiler installed I can use lower supply temps, ODR, other cool stuff

This run has about 60' of fin tube radiator on it, and the panel rad is near the beginning of the loop. I have the loop drained now so could switch it up on the boiler side so the panel rad is at the end of the loop instead, if necessary.

I did purchase the Runtal TRV set to go with it, and have a monoflo tee here too I could use if needed. Could I run the panel radiator in parallel with the one section of adjacent baseboard, using regular 3/4x3/4x1/2 Ts? Then if the TRV was open it would permit flow through the panel, or if it was closed, it would all just go through the adjacent baseboard?

 

[Bob Rohr]

I think the panel rad will present too much restriction, either as a series or with the mono flow if you have a TRV involved.

Treating it as a separate zone would be one way, but could short cycle the boiler if it was the only call.

I had a similar problem in my own shop when I added a bath to the radiant slab system. In the end I went with an electric Myson unit, 500W. It can be run on a timer, and setback if desired.

In your case, if 5 feet of fin tube was adequate, probably a 750W electric rad or towel bar would cover the heat load.

With the door open, heat from the rest of the home would cover some of the load, so the electric would not run continuously.

More info on panel rad piping.

http://www.pmmag.com/articles/86839-panel-radiator-piping-options

 

[heaterman]

We are currently in the middle of a similar project on a little larger scale.
The home was all baseboard and due to remodeling some of it had to be removed.
We decided to plumb the remaining baseboard and 5 new panel rads into a 10 loop Caleffi manifold.
The manifold will accept different size fitting so we ran 1/2" pex to each of the new panels and used 3/4 " pex runouts to the remaining baseboard which is now divided into 2 zones, each with its own actuator.

 

[jeffesonm]

Thanks everyone for the helpful replies. I already have the radiator in the garage so too late for electric.

Just remeasured and there is 51' of baseboard on this loop. I plan to plumb the panel in series with the 5' section of baseboard adjacent to it, as depicted in that diagram above.

If I don't use the monoflo tee, will water just bypass the panel rad altogether? Maybe stick a ball valve on the main line to throttle flow if needed?

Any other steps can I take to maximize the chance of success given this plan?