Radiant boiler install - how does it look?

Radiantamateur

Finishing up installing an IBC HC 13-50 mod-con boiler to feed a one zone radiant system (joist retrofit). Piped using primary secondary configuration.

Still have a few things to finish up, such as the 3/4" drain from the pressure relief on the boiler, and the drain from the backflow preventer to name a few.

Other than that waiting for the guy I bought the boiler from to convert it to propane for me and do combustion analysis and all.

Let me know how it looks. I will admit I'm not a plumber but did a lot of research and figured I could handle a simpler system. Anything that needs changed or that I missed?

Radiantamateur

Pictures.

Zman

Very nice job! What is your day job?
I think you will have difficulty purging the radiant loops. You will likely need a purge point on the end of the return manifold.

Radiantamateur

@zman thank you!

In order to purge the radiant loops I started at the manifolds. They both have a valve/drain on them, so I simply closed them off from the rest of the system and purged each loop individually, then worked my way from there around the rest of the system.

As far as day job I'm an engineer. I've dealt with a variety of things, from engine cooling design to most recently HVAC for the past year. Not really super applicable but does help understand things. I have to say though the plumbing portion of this has been a fairly fun project.

kcopp

Nice work. I think you will like that HC 13-50. I have a number of them out there. What is the design temp? Did you hook up the OD sensor?

GroundUp

Very nice job! Looks a lot better than most "professionals" will do.

SuperJ

Nice job. One thing I'm curious about is why you tee'd your secondary loop into your primary instead of the more normal primary tee'd into secondary? I think it's functionally equivalent. But it seems more intuitive to tee the lower flow loop off the higher flow loop.

How does your secondary flow rate compare to your primary flow rate?

I would recommend installing the system sensor on the secondary supply, this will help your boiler maintain the supply temp to the secondary loop even if the flow differs a bit. Not a huge deal since you only have one zone.

I'm considering purchasing the same boiler. Since I can't quite swallow the price jump to the SL series. My heat loss is 40kbtu.

Radiantamateur

@kcopp thank you. I am planning on running OD reset. I don't have my calculations handy (on my work computer) but I recall my max temp being around 130. The boiler itself seems like a good unit, but I don't know nearly enough about boilers to have an educated opinion. Decided on this unit based on recommendation from a friend and the cost was pretty good as well.

@GroundUp compared to most professionals though I don't have a time crunch and can take my time. No boss telling me to get on to the next job or being paid by the job, which probably helps.

@SuperJ I'm not positive what my primary flow rate will be. The boiler manual states a min flow rate of 2gpm and a Max flow of 9gpm. My secondary flow rate is 4gpm which is within that range. Is there a way I can figure out the primary flow rate? I'd think I'd need to know the pressure drop of the loop, which without knowing the internal pressure drop of the boiler would be difficult to figure out.

I did debate whether to tee the primary into the secondary. I went with the configuration I did after discussing with the guy who I bought the boiler from, and based on the majority of the layouts in the manual showing it that way. The primary pump can handle the increased pressure head, so I would think either one would work with the only con being the increased pressure head on the primary pump.

Radiantamateur

@SuperJ

Yeah the SL series definitely has some advantages, not to mention a larger btu range. This boiler does seem like a fairly simple design which I like.

If I were to do it again, I would be more inclined to use a hydro separater for ease of install and simplicity sake.

kcopp

Its my boiler of choice. Hands Down. I would install one in my house.... if I had gas

SuperJ

You can figure out your primary flow rate based on temp delta at max fire (known BTU and efficiency).
And then using the same formula you can figure out your secondary flow rate, since the BTU will be the same but it will have a different temp delta, just solve for the flow.

BTU = GPM x TempDelta x 500

If you know 2 variables you can solve for the third.

Alan (California Radiant) Forbes

Love the install - nice work.

We've installed two of the SL series boilers and I like the side tappings; saves my back and they're great for Munchkin change-outs.

Gordy

SuperJ said:

You can figure out your primary flow rate based on temp delta at max fire (known BTU and efficiency).

And then using the same formula you can figure out your secondary flow rate, since the BTU will be the same but it will have a different temp delta, just solve for the flow.



BTU = GPM x TempDelta x 500



If you know 2 variables you can solve for the third.

Differential pressure properly determined at the circulator is the most accurate.