New to site: New to radiant heat, bought house with it and HOLY CRAP

DanSmith3

So, moved into a new to me house. And man is this radiant heat nice. Cozy and warm.

As I investigate further I try to look into expanding it to a sun room I added to the house. The more I research radiant the more I realize the guy who installed it must have done a terrible job or not known what he was doing. Thankfully if I want to continue to path he has laid before me he has left me some ball valved taps on the header to do so. Rather, I'd like to ask you your advice on what I should do with this because I don't even know where to start.

I've attached a MSPaint Drawing of how my system is designed and installed. Also I have attached some basic pics from the basement/crawlspace.

Please review and advise as best as possible.

I think the biggest kicker was the fact that the supply and return lines are not at all connected except by heating zones meaning the recirc pump is pushing through the zone pumps????
*edit* Or rather the fact there is no "check" or "balancing" valves of any kind, Im really confused by this setup. I know there is a choice between using circs or zone control valves but yeah...

Anyway... any help would be greatly appreciated! I'm assuming pump pics are supply side.

Zman

That sure is an interesting way to do it.
How is the tubing heating the floors? Is it staple up? Plates? Concrete?
How big is the house?

DanSmith3

3200 sqft. Mostly baseboard radiators biggest zone is 4 loop under tile in kitchen foyer. 9 total zones/pumps/thermostats.

4 BR
LR
Kitchen
2 bath
Entry way

Zman

Well, It sounds like decision time.
The boiler is approx. 100% over sized and pumping is oversized by much more.
The first option continue with the system you have. Add the zone and install flow checks on each zone.
The second choice would involve a heat loss calculation, a new plan and sawzall.
I don't see a quick fix for what you have.

sonofaplumber

That junction box looks about as safe as a fart when you have the flu.

Paul48

More proof that home inspections are a joke.

Ironman

Definitely over-sized and over-pumped.

What controls the water temp to the floor?

Some more good news: your floor insulation is installed backwards. The vapor barrier should be towards the heat space, not facing the cold.

jjheat

No mixing valve for the radiant floor heat?? How is the radiant floor heat installed? In the tile bed, in the joist space, with or without plates?

DanSmith3

I did a heat loss Calc on the new room and room I wanted to add... just under 26k btu.

It's piped almost identical to figure 11 in the wiel mclain manual. The biggest issue I see is there is 0 control of return water temp.

As far as tubing, I've no idea specifically other than it there are 4 separate loops for the kitchen zone. Which has 1 themostat and one nrf-22. Which is the case for every zone actually.

I think there are only 2 zones that use the radiant tubing. Everything else is baseboard.

Zman

If you can, it would help if you could determine how the under floor pex is installed. If they just stapled tubing to the plywood, you may need the high temps.
Your calc for the sunroom sounds high unless it is 1,000 sq feet with lots of glass.

At the end of the day, how does the system heat? Are there rooms overshooting from the ghost flow? Rooms under heating?
What is the typical length of a boiler cycle? What is the typical return water temp?

DanSmith3

I assume it is stapled in the kitchen and bathroom zones.

Its a sunroom plus a room that was added in and not included in the radiant heat. I figured adding that room at the same time would help with the poor loading/oversized boiler and save me a ton of money as its heated electric right now. Its 650sqft and 10ft ceilings.

To answer your questions, at the end of the day if its not cold outside the kitchen zone does overheat the living space of the house. None of the rooms under heat, the only one that has under heated is my one bed room when it was -15 outside and has limited baseboard length and it just wouldn’t get over 65. However boiler water never dropped just didn’t have enough radiator.

I've not timed the cycle time but it doesn't seem to run very often because the only flow through the boiler is when zones are pulling it through and I think it has 10 deg of hysteresis. As far as typical return temp, I used to run supply at 150deg during the not quite as cold months, and up around 180 when it got cold outside. However, I looked a few days ago and noticed the return temp was 127 and got worried so I bumped it up to 160 supply and return raised to 135.

I have attached the plumbing pics from the manual Fig11 is basically how its plumbed and Fig 13 is probably what it should be.

My biggest concern is when I add 150ft of 3/4" line to the system at 2-2.5gpm, if it doesn’t kick on very often that could drop return temps A LOT regardless of what temperature I set the supply at.

I'm considering bridging the supply / return lines, adding a temp control valve / bypass to preheat some of the return water and adding a circ pump, and some check valves where there don’t appear to be any. That seems like the best and least intrusive way to make this right.