Bad Installation - Danfoss TRV

bb_7

Steve:

Since I am a former Danfoss guy I will put my 2 cents worth in..

Remove the valve on the supply side. It will clog and not let the condensate drain out eventaully. The opening is too small.

The operator must be placed on the vent for 1PS. If it's in a bad spot a remote sensor can be used. You can place the sensor below the radiator, but not right on it. This will sense the return air as it circulates through the room and modulate the venting accordingly. Once the room temp is satisfied no air will vent from the rad, thus stopping the steam from entering.

IF you would like more info, wander off of the wall and check out the library. Dan has a few good articles on 1 Pipe Steam that should explain it all.

Warm Regards,

bb

Steve_120

Bad Installation - Danfoss TRV ?

We just had a Danfoss non-electric TRV with remote sensor installed in a problem room that used to get too hot. The plumbers installed the valve vertically in place of the supply valve which is wrong according to the Danfoss web site and Dan's STeam Book. The valve overheats therefore the room is always cold. These guys have straightened out the rest of our one pipe steam system but I think they are wrong this time. Please help. Thanks.

Bob W._3

On one pipe steam the TRV goes in the 1/8" tapping for the vent. A straight shank vent goes in the TRV. Your plumbers put the TRV in as a supply valve on one pipe steam????? Also, its got a remote sensor? Are you sure you got the right valve body? My understanding is that you have to use a TRV valve body made specifically for one pipe. Steamhead?

Mike T., Swampeast MO

If the TRV operator has a remote sensor the orientation of the operator is irrelevant.

BUT, the remote sensor should be properly located. Believe that the preferred mounting distance for the sensor is from 10" - 20" above the floor. NOT under any drapery or blocked by furniture, well away from any drafts (e.g. a door or leaky window). Preferably on an interior wall--if an exterior wall such MUST be insulated. If wall is not insulated a piece of insulation (say 1/2" rigid foam) should be installed between the sensor and the uninsulated wall.

Brad White_20

Not always

A remote sensor (bulb) or remote sensor adjustment still connects to a head which has a piston and a volume of fluid or wax. It can be affected by the supply heat and react by closing. Not all models do this or share this but enough do that you should not place the operating head atop and inline over the supply pipe. An angle style with the head horizontally is preferred. Your points about sensor location are spot-on though.

The other posting about this being one-pipe steam is also correct. The proper application is for a thermostatic VENT valve (with vacuum breaker), not a supply-line (return line!) valve.

Mike T., Swampeast MO

Thanks Brad. I've never installed a TRV operator (have only used Danfoss) vertically. I don't even care for horizontal self-contained units on the bottom connection of standing rads but have done them that way when customer didn't want to spring for the remote-sensing.

Steamhead (in transit)

Right, Bob

on one-pipe steam, you use the valve body that replaces the air vent. Works on 2-pipe air-vent systems too.

If I remember correctly, remote operators are made to fit any standard TRV body including those for 1-pipe steam.

The solution here is to re-install the standard hand shutoff valve and mount a TRV at the air vent opening.

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Bill_17

TRV Installation

Allow us to clarify the questions raised. Bob is correct, a TRV for 1-pipe steam is a 1/8" valve that is mounted in the vent port of a radiator. A TRV for 2-pipe steam or hot water is mounted in the supply and often replaces the supply (hand) valve. Finally, and perhaps less known, TRV operators with any type of "remote" sensor can be mounted above supply pipes or above valves-as long as the sensor is in a good location. This is because the sensor has so much more fluid/gas than the rest of the control unit that it has virtually all "influence" on the TRVs operation.

Brad White_9

Remote sensors

I agree it depends on the manufacturer. I have several types in my house (each wave of renovation seems to have a type of valve associated with it!).

Without naming which one had the issue, I have Oventropp, Honeywell-Braukmann, Centra, Macon, Danfoss, T-A and one orphan that will not speak up. Geesh....

Any way, two that I have are installed with remote sensors, one has adjustment at the valve body-head and a remote bulb, the other has a "remote sensor and adjustment in one" and a similar reservoir/mass on the valve body. I would have rotated the heads horizontally but could not on account of space. Poor planning on my part.

It is these types that picks up the heat. While it has not closed the valve entirely, it has picked up enough heat to make those spaces noticeably cooler. I have the setpoint adjustments fully open and they do not overheat at least. Just my experience.

Still, excellent products, rather have them then not.

Yours are good comments though!