Pro advice on baseboard remodel?

Drew Stamps

I'm tackling one of those ever-expanding home remodeling projects (I'm the homeowner), and time has come for heat. I've read Dan's excellent Pumping Away and Hydronic Radiant Heating books, and hopefully I've learned enough now at least to ask coherent questions.

The 1959 house is entirely heated by hydronic baseboard on an oil-fired hot water boiler. The boiler is only about five years old, and the baseboard works reasonably well, so I'm planning on just extending the baseboard to the new enclosed space (formerly garage and screened porch, soon to be a modest sized bedroom suite).

Wall space in the new bathroom won't permit baseboard, so I've toyed with both radiant floor heating and a towel warmer/heater as heating options. I may get wild and do radiant floor plus a small towel warmer. The attached diagram shows my current system in black, and my planned addition in blue.

Dan's books included an idea for the radiant floor, but I kind of made up the towel warmer connection on my own. (I haven't found any online discussion of towel warmers in hydronic systems, for some reason.) I know that the towel warmer will have a shutoff, and that it also will be 1/2 inch pipe instead of the 3/4 inch that makes up the baseboard.

I think my current system will have enough spare capacity to handle what I want to add. What other questions do I need to be asking (and answering)? Am I barking even in the direction of the right tree?

Many, many thanks.

--Drew

P.S. I know my current system violates the "pumping away" principle and probably offends in other ways, too. Please have mercy on me anyway.

Mark Eatherton1

If you knew it was wrong...

you're culpable for any damage it might do. If it does any... That pumping away thing , or lack there of will get you into a boat load of trouble. Especially like you've got it set up. Your opearting pressure will end up being the static fill plus the whole pump differential potential, and thats BEFORE it get up to temp. Can you say popping off relief valves??? I can:-)

Is there a right way to do things wrong? Or a wrong way to do things right... I dunno. Which is the lesser of the two evils...

ME

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ALH_3

More than one problem

You only want the towel warmer to work when the "medium new baseboard loop" is hot? Same with the radiant floor?

Your system has some flaws, but must be working ok right now. Pipe the radiant floor and towel warmer to the boiler on their own circuits. The radiant floor wont work the same as the baseboard. You'll want the towel warmer when you dont want the baseboard hot.

Even without those issues, you still have that delta-p in the "medium new baseboard loop" which will starve it for flow if any of the other zones call at the same time.

Sure the boiler is big enough? If it is, consider some boiler reset with a tekmar 256 or 260. Watch out for warm weather shut down on reset controls when operating the towel warmer.

Consider using a panel radiator in the bathroom instead of the towel warmer. Hanging towels on the warmer affects the heating output. You could pipe it like two new baseboard loops and forget the radiant floor for such a small area. Just one idea.

-Andrew

Drew Stamps

Thanks, Mark.

I should have said but didn't: The existing system is NOT my handiwork. I think most of the layout is original circa 1959, although the boiler (and presumably the circulator) was replaced about 5 years ago, when the previous owner was here. I've owned the house 2 years.

Feel free to rag on the existing system -- I certainly won't take it personally. I can say that in the last two years, no relief valve has popped. I'm assuming, perhaps naively, that I can extend the system with "more of the same" and not get into any new trouble. Am I kidding myself?

--Drew

Drew Stamps

Thank you, Andrew.

There are definitely flaws. As I replied above -- the old flaws were "inherited." I just want to minimize the new flaws I introduce myself.

The new bedroom/bath isn't mine, but the family member who'll be there is really keen on a towel warmer. Maybe I should just go electric with that, and keep it out of the hydronic system altogether. The delta-p you're worried about is because of the towel warmer, right? If it's gone, the problem goes away, doesn't it? (I was thinking that the differential-pressure valve would take care of the pressure issues for me. I guess it won't.)

I originally planned to use a panel radiator instead of radiant floor or a towel warmer, but plans kind of evolved. I really like the idea of a warm floor in a bathroom, and it looked like a small bit of radiant floor hung off the baseboard loop would be pretty simple. The whole house is just one zone, and the radiant floor circulator would just run at the same time as the primary circulator, but at least there wouldn't be icy-feeling tiles all winter long...

Oh, and one new question: will a small, water-lubricated circulator for the radiant floor be pretty quiet? (The same family member mentioned above is worried about the noise.)

As for boiler size: no, I'm not 100% sure it's big enough. However, it has ample heat for the existing system without running constantly even on cold days. And the old house has got crappy insulation (mineral wool or fiberglass -- I don't know the difference by sight -- but it's all collapsed and falling apart). Once I beef up the insulation (on the to-do list), I should effectively gain a good bit of capacity in the boiler, shouldn't I?

Thanks again,

Drew

Ted_9

Questions

1) Is this a cast iron boiler, if so how old?
2) How do you plan on dealing with the low return water temps from the radiant loop?
3) If your going to do work, why not repipe the boiler and do it right, so that you dont have problems?


PATRIOT HEATING & COOLING, INC.

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hr

Or you could

install some electric radiant in the floor, walls,and panel radiator. It may be less hassle, expense, and much more controllable than trying to cut into that hydronics.

There is a time and place for small electric systems. You may be in a position to take advantage of it Mats, cable, copper plates, 240, 120, even 24 volt systems are available for DIYers. Hire an electrician to get code approved GRI circuits to the room.

hot rod

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ALH_3

Piping

I would suggest moving the radiant floor circulator and mixing valve to the mechanical room, and running two pipes while you're running the new baseboard loop. It's likely a small enough area that it isn't going to shock the boiler any more than the baseboard does. It certainly isnt going to induce condensation.

Another strategy for running the towel warmer is to get a brass or stainless one and pipe it into the hot water feeding the shower/tub. If that's not an option, I'd go electric for the towel warmer unless you run a third set of lines from the mechanical room. If you have outdoor reset controls, that can further complicate the issue due to warm weather shut-down.

Don't go electric for the floor when you have access to a boiler. It would be cheaper, but you'll have to "pipe" electricity to the room anyway. Why not pipe water?

-Andrew

Drew Stamps

Wow, what a range of opinions!

First, thank you ALL for taking the time to help me!

Opinions range from "don't cut into the hydronics at all" to "rip out and fix the entire boiler room piping system." I guess my ultimate solution will probably fall somewhere in the middle.

I respect the electric option (which could prevent a DIYer getting in over his head), but I really don't want a piecemeal heating system. I know I want to keep as much as possible hydronic.

I'd really like to keep all the new stuff on one loop, too. The in-floor piping is going to be basically unreachable once the floor is down, so I want to minimize the number of pipes and number of connections. (I've been reading another thread about PEX with interest, since that may be one option.) This new addition also runs a pretty good distance from the boiler room, so two loops would be two long loops.

My main reservation about hanging this tiny radiant loop off the new baseboard loop is the potential noise of the new small circulator. Is there any information anywhere about noise levels for circulators? Are they pretty quiet? (I recognize that moving the circulator to the boiler room would solve the noise issue, but again, I hope to keep to one loop.)

The boiler is cast iron (about 5 years old), but I'm predisposed to think Andrew is right about the return water temperature issue. The radiant floor is a small area, and the cold-water output from it is only going to be to offset the little amount required for makeup hot water from the main loop. Mixed in with the water from all the other baseboard loops, I wouldn't expect it to make much difference in the final return water temperature.

As for the existing boiler room, I understand that it would be better off piped differently. At the least, I should move the fill valve with the pressure regulator somewhere other than the suction side of the circulator. And, ideally I should reposition the circulator and pressure tank, etc., into a proper "pumping away" system. With everything else I've got to do, though, there's a big part of me that wants to leave well enough alone. It's working now (and apparently has been for 45 years), and as a DIYer, I could always screw it up worse while I was trying to "fix" it.

Finally, for clarity, here's a new diagram with the towel warmer removed from the hydronic system. I think the towel warmer is a dead issue now.

Further thoughts and commentary are greatly appreciated. I'm learning a lot!

Best,
Drew

Ted_9

Drew, tell us again why this job cant be done right the first time? I'm not being antagonistic, but for once, why cant a "DIYer" come in here and ask to do it right, and actually do it!

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Drew Stamps

So, you're volunteering...

to come over and help? ;-)

Anyway -- it can't be done right the first time because it was already done wrong. The "first time" was ten years before I was born. Maybe that's just a matter of semantics, though.

You're not talking about me doing my add-on project right so much as re-doing something wrong to make it right. If I find that the boiler room has to be redone for me to get my new project to work satisfactorily, believe me -- I'll do it.

I do appreciate your dedication to the craft, and I actually respect the fact that it annoys you if someone adds on to a half-**** set-up rather than reworking it. I'm that way myself on most things. But honestly the last thing I really need right now is for this project to grow any larger in scope. The heat is about 5% of what I have to do, and every time I sneeze there's something else unexpected I find I have to tackle.

Best,
Drew