At what temperature will a pumped coil freeze

bigugh_4

32 degrees if the water is pure. if the water is conaminated, a little less. also depends on the flow of air through the coil. If you want freeze protection, give your self some leeway and set the freeze protection st 36 degrees. Pumped water, is moving however if the latent heat of freezing is removed faster than it can be replaced, walla, the freeze occurs, and all its other complications. Even Nigagra Falls has been known to freeze.

Arnold E. Clubine

Frozen coils

Looking for data on at what temperature a pumped coil will freeze

don_163

it depends

on if the wind is blowing.Time.. as to how long its exposed to temp below freezing.Also as to rather it has any glyco in the system and, if its been maintained.

Ummmm...........

clammy

freeze stat

When ever in the past and future i always install a freeze stat wired to the 3 way valve or pump depending on the set up but i have never installed a hot water coil with out a freeze stat it's very cheap insurance for freez protection espically if there's dampers and outside air .If using a 3 way valve for temp control it's no big deal but just running the pump and expecting it not to freeze because the water moving is a little risky to me personally .Peace and good luck clammy

Aidan (UK)

At what temperature will a pumped coil freeze

Freezing........within milliseconds of the water temperature dipping below freezing. Anti-freeze lowers the freezing point. How did I learn this lesson? Best not to ask, but it did involve 3 coils handling about 12.5 cubic metres of air per second and the coils' sudden demise was recorded on a BMS/DDC graph. There was a low temperature thermostat which shut the plant down when the heating failed; some clever person (not me) got it running again by putting a polystyrene cup over the thermostat. Repairs were about £3,000 ($5,000?), some years ago.

Piped services in buildings often won't freeze if the outside temperature is dipping below freezing overnight. It will typically take some hours for the inside temperature to drop below freezing. Coils handling outside air will freeze instantly because there is a large heat exchange surface with freezing air passing over it. The water flow rate will have little effect; the boundary layer adjacent to the pipe wall is static, so that freezes and the freeze progresses towards the centre.

The usual specification is a manually reset thermostat, hard-wired (i.e., not a signal routed through DDC software) to stop the fans and close the air inlet dampers. The dampers have spring-return to closed actuators so they shut in the event of a power failure. The thermostat can be in the air downstream of the coil or an immersion thermostat on the coil outlet connection.