PDA

View Full Version : ground source heat pump problem


Lc_shi
28-03-2012, 03:32 AM
Dear sirs
One GSHP (22KW) is working normally in cooling mode but turning to heating mode and after running about 3~4minutes the LP drops continuously and reach to LP protection and this failure repeats and not disappear . What is the reason? need your help.


rgds
LC
mad fridgie
28-03-2012, 04:09 AM
Condensing pressure is to low, which causes a low suction pressure. You need to restrict the heat of rejection medium (if air slow the fan down, if water slow the water flow down)
Lc_shi
28-03-2012, 09:47 AM
The HP is around 8 bar and LP is around 4 bar. And the heating can operate stably at 4bar for 3~4minutes and then begin to drop.
The Viking
28-03-2012, 05:38 PM
Let me see....

Hmmmm....

The finger I'm holding up feels wet...
My tea leafs are slightly darker than normal and the coffee bean is laying on it's side...

-You got air in the water works!

No???

Maybe we could do with some more detail then...

Make and model?
System layout?
Water - water? Water - air? Refrigerant - water or air?
Accumulator?
Refrigerant used?
Sub cooling?
Super heat?
Discharge temperature?
Temperatures of air or water in and out?

The above would give us a fighting chance to get the ball rolling...

:cool:

.
Lc_shi
29-03-2012, 04:23 AM
Make and model?
System layout?
Water - water? Water - air? Refrigerant - water or air? (water-water)Accumulator? yes
Refrigerant used? R22Sub cooling?
Super heat? 5
Discharge temperature?
Temperatures of air or water in and out? ground 11/15C room side 16~19C
The Viking
29-03-2012, 05:56 PM
So you got a water to water heat pump operating on R22.

8 Bar discharge gives a saturated temp of just 19.7 *C, way to low. Subcooling?
4 Bar Suction gives a saturated temp of 0.1 *C with 5*K superheat, a bit low but within range...

First suggestion,
Try reducing the water flow on the hot side until your discharge maintain a steady 16-20 Bar then take new readings.
The readings need to be as accurate as possible and we do need water IN and OUT on both hot and cold circuits as well as both sub cooling and super heat together with the pressures of the refrigerant.

Good luck.

.