can testing a system bring more harm than good

[Yuri B.]

There are three water chillers (R134a) on a site. Two are working more or less bearable but the third triping on LP. I heard a version its evaporator to be dirty, but I have spent several days measuring SHs, SCs etc on all systems, and besides, water pressure drop on this is even the smallest. My version is shortage of refrigerant.

But can what I insist upon - decanting (to weigh against the norm on the nameplate), vacuuming and pressure testing - turn more harmful than letting things status quo ?

Both are refrigerant-to-water - the evap and condenser. If a burst develops during the procedure and the system sucks in water it will be disaster ! Maybe let the sliping dog lie and recommend just adding from time to time some refrigerant ?

[Brian_UK]

You say that the water pressure drop is the smallest.

If this is the pressure across the evaporator then it would indicate a low water flow unless you have some other form of water flow measurement available to contradict this.

[Gary]

Both are refrigerant-to-water - the evap and condenser. If a burst develops during the procedure and the system sucks in water it will be disaster !

Not to worry. The compressor valves will break long before the condenser bursts.

[Gary]

... and recommend just adding from time to time some refrigerant ?

Or maybe find the leak and fix it?

[crit71]

Or maybe find the leak and fix it?

:D Yeah, pressure test, repair and vacc would be a good starter I reckon. I've just been on a poll about breaking regs too. lol.
Aaaah, I see he's not in the UK;)

[RANGER1]

Isolate water and drain if your worried .

If its shell and tube evap or condenser the tube plate should be leak tested anyway for leaks .

[lowcool]

wouldnt have thought it would be running in a vaccum,different designs for applications i spose lol

[Yuri B.]

Thanks for all your replies.

By Brian UK:


pressure drop is the smallest.

If this is the pressure across the evaporator then it would indicate a low water flow


I always thought the more is obstacle in a section the more input/output P drop it will cause (across the section)?

Before the all the evaporators there are 2 pumps, only 1 is being used.

One manometer is at input of the evap (after the pump) another at evap's output.

P drop is 2 B on the "good" chillers, and only 0.4 B across the evap of the "bad" one.

Have experimented with water flow: half-closed the valve (before the pump) - P drop had not changed very much, switched on the second pump - again P drop remained the same.

Motors in pumps (seemingly the pumps themselves as well) are identical, those at "good" chillers draw 22A, the motor of the "bad" one - 18A. But: the "good" chillers are a bigger model (York LCHH....130) than the "bad" (LCHH...110). So for el current difference I would account solely by difference in evap-s sizes.

[Yuri B.]

By Gary:

Not to worry. The compressor valves will break long before the condenser bursts.
Besides, the condenser has a safety valve (only is it reliable? the chillers are 8 years old).

By Ranger1:

Isolate water and drain if your worried .

It is not to do at this hot time. I get at least the second system on this chiller to work more or less bearable: neutralized one relief valve (put a magnet instead of solenoid - when valve energized or with magnet one head is excluded from work), and reduced flow through condenser. (one drycooler serves all 3 chillers simultaneously)