Freeze question ?

[Octopus]

I'm in south Florida and I severely doubt it could happen but how cold would it have to be for how long to freeze a plate heat exchanger, it's a 200 ton chiller so the heat exchanger may hold 20/30 gallons of water. No glycol or brine obviously in Florida. No heaters no water flow.

[klove]

That's a loaded question, Chris. What has to happen is for the water to freeze solid. According to what I've studied in physics, water starts to expand around 34 degrees, and the expansion rate increases once the fluid is totally frozen, thus causing the rupture. Since water freezes at 32 degrees, theoretically a freeze rupture can take place at that temp if it stays there long enough. Obviously as the temp drops, it takes shorter time frames to freeze, and alot of the answer in this case would be dependent on surface area of the HX, what is it mounted on, what is it insulated with, etc. Takes a LONG time at 32* to do damage, but who's to say at 10* (which is what it's been on my front porch the last three mornings). If you're concerned, you may want to stick a heat lamp on it temporarily - that's what we do. Better safe than sorry.

[heavymetaldad]

10 in 'bama!!!!!!!!! what is this global warming?

[klove]

10 in 'bama!!!!!!!!! what is this global warming?

Where I live is 1 of the 2 coldest places in our fair state (the other being Valley Head). Consistently 6 to 10 degrees colder than other places in the same latitude, depending on wind direction and speed. We've often wondered about this so-called global warming thing............

[flange]

run the pumps

[Octopus]

Can't run the pumps boiler's on same loop. Thanks for the suggestions guys.

[txhvac]

Sounds like it's a two pipe system, just drain it, it'll be isolated.

[referteacher]

Can't run the pumps boiler's on same loop. Thanks for the suggestions guys.

Crack the valves and run warm (HOT?) water through it????????

NAH. Too risky.!!!!!!!!!!

[pecmsg]

Why, can’t you run the pumps with limited flow?

Your below design conditions do what you have to protect the equipment.

[referteacher]

Why, can’t you run the pumps with limited flow?

Your below design conditions do what you have to protect the equipment.

If it is a two-pipe system, the water from the boiler circulating through the pipes will be too hot to circulate through the chiller. Excess pressure will lift the relief valves and blow the refrigerant charge.

[chillerguy81]

Could drain it and pump er full of glycol if you won't be using it for awhile.

[bamatech]

If in doubt drain it.This weather should only last a few more days.Has been in mid teens in my section of bama this week. We have been patching burst coils on units all week after gas supply on boilers failed 2 nights in a row.ARRRGH.
I want my global warming, Where the heck is it ??????

[just chillin']

I'm in south Florida and I severely doubt it could happen but how cold would it have to be for how long to freeze a plate heat exchanger, it's a 200 ton chiller so the heat exchanger may hold 20/30 gallons of water. No glycol or brine obviously in Florida. No heaters no water flow.

Chris that's pretty risky not having a working flow swicth on your chiller .Draining the evap may not work for you either because plate heatexchangers have a V type passage in them that do not drain .I would suggest Heat race wire set up on a outside thermostat to energize below your safe setpoint and interlocked with the chiller so it is not going to come on if your running the chiller.

[just chillin']

I'm in south Florida and I severely doubt it could happen but how cold would it have to be for how long to freeze a plate heat exchanger, it's a 200 ton chiller so the heat exchanger may hold 20/30 gallons of water. No glycol or brine obviously in Florida. No heaters no water flow.

Chris that's pretty risky not having a working flow switch on your chiller .Draining the evap may not work for you either because plate heatexchangers have a V type passage in them that do not drain .I would suggest Rap the evap with Heat trace wire set up on a outside air thermostat to energize below your safe setpoint and interlocked with the chiller so it is not going to come on if your running the chiller.