Heating Help

Myson Low Line Convector

While I have the drywall removed I am considering
adding supplemental heat to a bedroom above our garage. The system will also be
supplying supplemental heating for the tile floor in our master bath and another
small bath. I am looking at the Myson low line convector line and my water
supply temp will be around 120˚F. Anybody here have experience with this line?
Would you recommend a different brand of convector for low temperature hydronic
supplemental heat?

http://www.myson.co.uk/products/lo_line_rc.asp

Thanks

why not radiant?

Any particular reason you're looking at a convector?  Myson makes quite a range of plate radiators, many of which are quite affordable.

Myson has charts with derating factors for various water supply temps.  Are you running outdoor reset?

I should have said fan convector

Thank you for taking the time to respond. I should
have stated I am considering their fan convector for supplemental heat. Specifically
their Lo-Line 9-6RC. I will be running outdoor reset. Below is a picture of my
panel and heat source. It has been a big challenge moving the water heater from
the second floor to the garage. I ended up replumbing almost the entire house
and there were many fire code issues to resolve.

Again this is just for supplemental heat and our winters are not that cold.

What happens...

What happens if the water in the square bucket freezes and the pressure relief valve opens and wants to discharge over pressure or over temperature water?

What happens of the water in the square bucket freezes and condensate must be discharged from the hot water heater?

Your scenario will never occur

The bucket is there to catch the condensate
until I finish installing a sink to the left of the water heater and a standing
pipe will be installed to the left of the sink. A condensate
pump will be installed below the radiant expansion tank and the condensate
will be pumped to an air gap attached to the top of the standing pipe. The
discharge line for the TPR valve will just discharge to the floor when the
installation is complete

BTW, the temperature in our garage never gets low enough to freeze water and there is an expansion tank on the cold water supply line to the water heater.

rest of the system?

Do you have room-by-room heat loss and radiation numbers?  What is the rest of the radiation like?  Outdoor reset curves for convectors are different than for radiation, though controls can make the two play nice together.  Still curious about the fan convector when the rest of the house is radiant.

I'm guessing the power vented tank heats DHW and the X-block isolates the heating system from that?

Been Busy The Past Week

Actually a high efficiency gas fireplace on the first floor will heat the house. Our
neighbors with the same floor plan tell me they are happy with this
arrangement. When we pulled all the drywall on the first floor doing other
repairs we discovered significant structural damage done by the original
plumbing contractor and serious code violations. I decided to redo the plumbing
and move the water heater from the second floor to the garage. Since the
ceiling was open and the floor under our master bath was open we thought we
would install supplemental hydronic heating under the subfloor. The tile is
cold in winter.

When I removed some of the drywall in the garage to upgrade the plumbing I figured I
would install the extra Joist Trak and PEX tubing left over from the master
bath installation under the subfloor for a smaller bathroom over the garage.
Again, just supplemental floor heat for the bathrooms.

Then I started thinking it might be nice to have supplemental heat in the bedroom
above the garage in case the fireplace downstairs is not sufficient on the
coldest days. I saw Myson made a low temperature hydronic fan convector and
thought it might be a good solution running the same water temperature as the
floors.

Since my last post I discovered a crack in a 2x12
joist knothole where I had planned to run PEX to the front bedroom. I wanted to
repair this properly and contacted a structural engineer to do the calculations
for me.






 





I installed the repair pieces yesterday and now I can run PEX to the
front bedroom. I don’t have to install a convector right now, but I could run
the PEX to a stud bay in the bedroom and decide later if I really need the supplemental
heat.





 

I like Myson

but the question is how is it triggerred? If it's second stage, and you won't need it until the water temp is over the minimum temp of the aquastat that allows the fan to run (standard on most units like this), then you're good to go. In fact if you can dial that aquastat to the water temp you'll need supplemental heat at, you might even skip external staging. but that's a tinker system.

typically I would do a panel radiator sized for the max temp of the system and the supplemental load and let it vary its output with your reset curve.

The aquastat is adjustable

Rob,
The Myson fan convector has an adjustable aquastat for low water temperature applications. I planned to use zone valves connected to thermostats to control each zone.

is it really an aquastat?

or is it a TRV?

TRVs might be a batter choice than zone valves for most of those rooms.

Like Rob, I would most likely specify a plate radiator (like a Myson Select) sized to the floor loop temp. With a TRV, of course.

I may be mistaken

but I think they are only adjustable down to 110 deg f. not so good for a radiant reset curve unless, again, you can take the tinker route and use your reset water temperature curve as a proxy for when you'll need stage two help. that's unlikely to be perfect but it is cheap.

if you are using a stage 2 thermostat though, and can keep up until you need water temps that high, you're golden.

Thanks for the comments

Been busy. Discovered termite damage and kick out in
the subfloor adjacent to the main support beam (4 x 16) that spans the garage
and supports the second floor and roof load. It looks like the termites entered
the roof parapets and they ate their way down the studs (termite superhighway)
to the garage. I ended up opening the walls in the bedroom above and injected
borates into the galleries.

Everyone’s comments have been very helpful and I have
decided to postpone installing a convector in the bedroom above the garage.

I also decided to abandon using Uponor joist trak under
the bathroom subfloor in the garage and will consider using Warmboard when we
remodel that bathroom next year. BTW, Warmboard is located just across the road
from us in Aptos. For now the hydronic system will just be supplying the joist
trak under the master bath tile floor.