Rheem Heat Pump -- Defrosting chain of events

[andersoj]

Sorry for the lack of model #, but I don't think it's really relevant.

We recently had a failure of our heat pump, and it took awhile for me to sort out what happened.  Here's what I've pieced together:

- Drain line for water pump froze over

- Heat Pump goes into defrost (cooling) mode, and starts sucking moisture out of the internal air

- Drain pump reservoir fills up with water

- Heat pump fan unit cutoff is triggered (silently!) by water pump switch

- Heat pump (inside) coils frost over in to one gigantic ice cube

I'm not totally sure this is exactly how things happened the first time, but it definitely repeated several times as I tried to get things going.  I defrosted the heat pump, located in our crawl space, with a big new propane forced-air heater.  I string some temporary drainage line to make sure I could keep an eye on it for a few days.

It's working now, air movement is back to normal, filters are clear, and the pump is working.  I've also listened to the reverser valve go through a few transitions -- it's a little noiser than it used to be, but it's 12-15 degrees out, so maybe that's expected.

Few questions:

- If I see frost all over the internals on the outside heat pump unit (fan is clear, but reverser valve and lines under the shroud were *coated* in inches of frost) AND I have the inside units' coils frozen over into a solid ice cube, does this mean there's something deeper going on?

- If I'm running a separate gas fireplace in the house in order to cut down on heat-pump electric/aux heating, is there anything I need to look out for?

- It seems nasty that the water pump can silently cut off the heat pump without raising a warning, though I guess I don't know how I'd get that warning.  Should I have a thermostat inside with some kind of alarm mechanism to let me know something has gone tits up in the bowels of the system?

JA

[applianceman18007260692]

Their is a float built into the reservoir, if the water don't get pumped out the float kills the system to keep from flooding the house with unwanted water. The drain pump is probo dead. What ya thank?

[Samurai Appliance Repair Man]

[user=4554]applianceman18007260692[/user] wrote:

The drain pump is probo dead. What ya thank?

Sounds like some might good thankin' to me, applianceman!

[andersoj]

Drain pump is fine -- the line was frozen, so it was pumping against about 8-10 feet of ice.  I routed a second drain line, and the drain pump is no longer an issue.  I also tested it with a 2-gallon jug of water brought down for the purpose.

The real concern, long term, is that I should be notified somehow if a failure of this type happens.  Any cutoff (from drain pump or otherwise) that disables the heat pump / blower unit ought to raise an alarm.  I'm shopping for indoor thermostats that have this capability...

Also, whatever caused the catastrophic icing ought to be avoidable...

JA

[applianceman18007260692]

What you can do is put some thermistically controled heat tape on the drain pipe to keep it from freezing like they use in modern walkin coolers. You wrap it around the drain pipe. If the pipe gets below freezing the wires in it heat the pipe keeping the water from freezing.

http://www.chromalox.com/productcatalog/Heat+Tracing+Products/Light+Commercial+Cables+and+amp%3b+Controls/Heating+Cable+-+Pipe+Freeze+Protection/product-details.aspx?p=316

[Bobice]

Go to www.WayneShirley.com RSES's heat pump guru