thermostatic valve install Q

Jim_66

Hello All!

We have a room with a badly oversized hot water radiator (13 section/3 column)that was clearly a "what we got" replacement (after a freeze) for a once properly sized radiator. The room is just 9 x 8 feet.

I've decided that the best we can do short of replacing it would be to add a thermovalve...

I dont want to do it myself at all, but with truck roll charge and minimums I've been getting estimates of around $500 to do the job. Its just too small a job and I think with the heating season coming most contractors think its a waste of their time.

So, I guess I'll do it.

I'm wondering if there are any gotchas or special considerations when it comes to ordering the valve--and if anybody has opinions on brands (danfoss vs. honeywell, maybe myson makes one--any others?)

The current hand valve is tucked into the corner of the wall (see pic) with anbout 6 inches clearance, this will make the install difficult, but aside from that--do you think this means I should get a remote sensor for the valve to work properly?

Thank you thank you thank you!

Mike T., Swampeast MO

Danfoss valves (with actuator) extend about 4" beyond the edge of the pipe. A bit less if the remote actuator is used but it's still an attachment to the valve body.

Danfoss calls the valve body "side-mount angle" in that application. Not sure if others use the same description.

Make certain you install on the supply side. Hand valves are usually but not always on the supply. Verify through the piping if at all possible. It won't work if installed on the return.

Worst part (to me) of a job like that is draining and re-filling just to do one little thing--that's likely a big chunk of the cost.

John Ketterman

I am a homeowner and installed several TRVs myself. It was, shall we say, a learning experience. It gave me a greater appreciation of why plumbing professionals charge so much. It's not the work, it's knowing what to do and what tools to use. It took me about 10 times as much time as it would take someone who was qualified.

As already stated above, TRVs with built-in sensor have to be installed with the actuator sideways. If your current valve is on the supply side of the radiator, it looks like there is not enough space for a TRV. If the supply is actually on the other side, you are in luck. Manual valves don't care but TRVs do.

In an old radiator, an awful lot of force is required to unscrew the three things you need to unscrew to get a valve off. I had a 24" pipe wrench and 24" adjustable wrench but still needed to use an extender in many cases. Plus I used a propane torch to loosen things up. In one case I had to cut away the part that screws into the radiator, using a reciprocating saw from the inside. Not pretty. (If yours was recently installed, it may come off more easily.) Remember, you also need a radiator spud wrench.

Also note that the radiator has to swing sideways to remove/install a valve in cases where the riser does not have enough play. For larger radiators I devised a method using one of those 24" wrenches as a lever to raise the radiator just slightly so I could jog it sideways. One of the radiators was 10 ft long and too heavy to move even a little bit, so I had to cut away part of the oak floor to give the riser enough play. (The damage is hidden by the escutcheon.) Maybe there is a better way but I couldn't think of one; a professional would have known.

In summary, your mileage may vary, but I should not have tried to do it myself. (It's done now, though, and everything works.)

PS You should consider putting TRVs on all radiators, not just this one. People get used to the huge temperature fluctuations of bang-bang heating, but once you have TRVs you'll really notice the comfort. If heating people are too busy, ask plumbers if they are familiar with TRVs; their work is not so seasonal and they are used to doing smaller jobs. And it won't cost $500 per TRV if you do several; probably closer to $200 per TRV. You may save money by offering to drain the system in advance yourself. But let them refill because you need to be sure there are no leaks.

John Ketterman

> Danfoss valves (with actuator) extend about 4"

> beyond the edge of the pipe. A bit less if the

> remote actuator is used but it's still an

> attachment to the valve body.


If using a remote sensor, can't one use the type of right-angle valve body where the actuator will be vertical? I believe Danfoss makes them. Seems to me that if the sensor is not directly on the actuator, it should not matter which way the actuator is oriented.

John Ketterman

There may be quick-and-dirty ways to reduce the output of this one radiator if you're happy with your system otherwise.

(a) Close the valve and then crack it open just a bit. Some experimentation is needed. Radiators are not very sensitive to flow rate. Half or quarter the flow often makes no noticeable difference to the heat output. You have to cut the flow rate by a lot to make any difference, but without shutting it off completely.

(b) Drain radiator so that it is 1/2 or 3/4 full of air. Again, you'll have to experiment till you get it right.

(c) Cover the radiator to reduce its output.

Of course, a TRV is by far the best thing, for all your radiators (except one in each zone).

Jim_66

yikes (in response to J. Ketterman)

Wow--Well, I really appreciate the real-world/homeowner perspective.

As I said, I dont want to do this, but the prices I quoted dont even include the valve. Since my time is cheap, its worth it to me even if it takes a few days.

You've given me alot to think about though...and I take your advice very seriously. My hope is that with much planning I can get away with this. I was already planning on a fight with the piping--I've replaced hand valves once or twice so I know thats no picnic. The current valve is frozen open so theres no way to throttle it--a TRV is definately the way to go IF i can make it work with the orientation issue.

I guess Im just glad to hear that it works for you in the end--If I can get there somehow thatll make me happy!

regards
-jim

Mike T., Swampeast MO

Yes, sorry. That's the "angle" style. I do though believe you have room for the self-contained version as it takes very little additional room to install the actuator. Unless there's a door or window VERY near that corner, the location shouldn't be a problem. Of course it's always a bit of a pain to stoop to adjust TRVs attached to the bottom of a rad...