Zone valve very close to rad- will it be too noisy?

spudwrench2

(Hot water, 2 pipe direct return system with panel rads) I've got a room that runs a little hot. (Rad was oversized from the get go, then I made things worse by remodeling and insulating the room.) I blocked off the top of the rad with aluminum foil and have the manual valve throttled down pretty hard. Much better now, but still runs a couple of degrees hotter than the rest of the house, especially when two people are sleeping in the room.

I don't like the idea of TRVs. Sensor head way to close to the rad to get a really good read on room temp, the remote ones use that capillary tube thing which seems fragile and unsightly, etc. Maybe I'm wrong, but I'm also stubborn. :-)

My plan is to add a single zone valve to the pipes going to this rad, another thermostat and transformer. It won't be piped or wired so it will be able to call for heat, but the zone valve will be open when the temp in the room is below the room's t-stat set point and closed when it's above it. Sort of an electronic, bang on/off TRV.

Will one of those cheap Bluefin zone valves be noisy or unreliable? I can go for a Taco 570 if need be but they are kind of expensive. The valve is going to be located directly underneath the rad in the basement, so I'm concerned that a motorized valve might be a bit loud. Any recommendations? Is this a silly idea?

dopey27177

Need to use a slow operating motor on the valve.

Jake

Mad Dog_2

Yes. I agree Mr Myron, And never try to save a buck on Plumbing and heating materials.  It rarely works out.  Taco is a great product and company. Mad Dog 🐕 

hot_rod

It’s the spring return that makes the noise, the are quiet when motoring open.
A thermal actuated ZV would be silent, theses are low current draw versions.

Rethink the TRV. TRV would work just fine, it’s a non electric proportional control, much nice way to control instead of bang/ bang. There are millions in use around the world.

kcopp

have you tried a trv? before going to all the trouble of a ZV I would at least give that a go.
They also make remote TRV... https://www.supplyhouse.com/Honeywell-Home-T104F1512-High-Capacity-Thermostatic-Radiator-Actuator-Remote-Sensor

Im sure you can find one that fits.

Mad Dog_2

I'm a big Fan of Tunstall/Macon controls
TRVs...high quality, very fair price, yiu can talk to the owner,, Woody great guy, made in USA!  Win win!   Danfoss is great as well but I'm always going with USA when I can.  Mad 🐕 Dog. 

spudwrench2

That Caleffi zone valve with the unions is great idea. I don't trust myself 100% to sweat a zone valve w/o cooking the guts, so I was planning to disassemble whatever I installed before sweating it. Unions are a much more elegant way to isolate it w/o having to strip down the valve.

I'll think some more about TRVs, but the rad is mounted on an outside wall. A TRV with a local sensing head is going to be 6" or so from the rad- how can that be a good read of the room temp? Would you install a regular thermostat that close to a rad? The TRVs with the remote sensor would need a quite a long tube to reach an inside wall due to the layout of the room. I know the Europeans love them, but I just can't do it.

hot_rod

Press tailpieces are available on all the zone valves.

TRVs have threaded and copper compression options!

Eye level isn’t ideal for thermostats either, if you sit or are in bed the majority of the time in your home.

There was a movement years ago to lower thermostats but it is the convience of eye level over the function that wins

mattmia2

You could use a trv type valve and a heat motor actuator, those are mostly silent.

You can pick a threaded valve then you can sweat on adapters and screw in to the valve body. Or the numerous options @hot_rod mentioned.

spudwrench2

Well, I said I was stubborn and dead set against TRVs. I bought the Caleffi zone valve (1/2" sweat was out of stock, so I used a 3/4" valve and some reducing fittings), had a spare T87 stat , bought another 24V transformer and put it all in.

I was initially planning to mount the ZV in the basement, but the clearance to a joist was really tight on the supply line. I could have installed it in the return line easily, but that would have meant draining down the whole system during heating season. (the only shutoff in the return line is the angle valve at the rad, the supply line has a ball valve shutoff in the basement.) So, I put in in the room by the rad.





It's working really well. The valve is silent, the room is holding a steady 66 deg (The T87 is a little out of whack both in the room temperature readout and temp setting, but as long as I know 64deg setpoint= 66 deg room temp, we're golden.)

Thanks to everyone who offered advice, even if I ignored some of it!

mattmia2

That t-stat has to be level to be accurate. The anticipator may need to be set close to the shorter end of the scale since that heat motor valve probably draws little current.

spudwrench2

Thanks for the tips! I did do both of those things- I think I set the anticipator to 300mA and I did level it out. I should probably double check the level though, it might have drifted as I tightened things down. The in room temp seems very steady, so I think the anticipator setting is good.

bburd

I'm not familiar with that zone valve, but the traditional Taco heat motor valves drew 0.9 A. A T87 had to be set toward the longer end of the scale to avoid short cycling.

spudwrench2

This Caleffi valve specced as <250mA starting current and 125mA running current, it's a low draw type valve. Could probably adjust the anticipator even further down, but everything seems to be working well so I'm inclined to let it ride.

hot_rod

That is a Twist-top, you can also manually open it if the t-stat fails, or power goes out.