View Full Version : Swimming pool heat pump

26-04-2014, 07:02 PM

I was sub contracted in by another firm to replace some parts to a heat pump that provides some supplementary heating to a large swimming pool at a local leisure centre.

One of the companies own engineers had been out and ordered the parts I was asked to fit.

I had basically been given every component that water side of the system; 4 big heat exchangers, various piping manifolds, float switches etc. I was told that the system had lost all of its gas.

On arrival and after speaking to on site maintenance team, I learnt that against advice they had been using undiluted acid to flush out the heat exchangers. They have an ongoing problem of blockages caused by human body fats from the pool return water. Nice.

Anyway, it was pretty obvious the acid had destroyed the heat exchangers and hence all gas lost.

I started removing the dead parts and soon realised we had big problems. I poured litres of water out of the exchangers from the refrigeration circuit side. I hoped that it would be contained at the exchangers but no, after cutting suction and liquid lines I found these too full of water.

I ended up completely dismantling the system and pouring water out from every component. I poured enough water to fill a bucket from the liquid receiver!

I am now extremely worried about the compressors on the heat pump! i was surprised but the insulation resistance has tested out ok on all of them! Just concerned that if the acid cleaner has entered the comps it could eat away at the windings after some time?

So far I have blown out the system with about 60ltrs OFN. I have a video of the water spraying out but can't seem to attach. I blew out until the nitrogen was coming out dry. I have then flushed through the system with endo-flush. I have changed oil in all comps, fitted new drier and I am now triple vaccing, have broken with OFN twice and left vac pump on for the weekend for final vac. Back on Monday to attemp start up!

What do you reckon? Has anyone else ever has anything like this? Have I done enough? Will comps go bang? I'm nervous to say the least...

26-04-2014, 07:13 PM
Sounds like you have done the best that you could.

Make sure that someone is aware of your concerns regarding the compressor due to the fluid that has been inside it.

26-04-2014, 11:47 PM
What was the condition of the oil in the compressors? Heavily contaminated and diluted?

27-04-2014, 10:11 AM
The oil was cloudy but didn't seem to be diluted... I haven't tested yet but suspect there will be a lot of acid present.

I have let the company I'm working for know the situation, and on site maintenance but I am really hoping that everything runs up ok on Monday! Have spent a lot of time on this now so hoping for a good outcome!

27-04-2014, 10:14 AM
Also hoping my vac pump has held up ok over the weekend! It has taken some punishment on this system! I put some fresh oil in it before leaving on Friday so fingers crossed....

27-04-2014, 05:23 PM
I once had a big York chiller with a burst evap. Water was in every part of the system including the condenser (air cooled). I thought it was beyond economical repair but the customer would not heed my advice. Anyway we isolated the evap and started to try to dehydrate the system, we had space heaters blowing through the condenser, a huge Edwards vac pump on etc. I spent almost two weeks changing vac pump oil and doing moisture tests. We drained all the oil out the added new oil,then got a new evap craned in and evacuated and ran up the system only to find the suction socks on both compressors choking up with sludge after about 1/4 an hour running. I must have cleared those socks half a dozen times and the sludge kept coming back. We then lost one of the comps and after that the customer decided to bite the bullet and purchase a new chiller. I hope it's not as bad for you but I was total pi---d off by the end of it all.

27-04-2014, 06:28 PM
Good luck on Monday, hope it works out ok.

27-04-2014, 06:44 PM
personally I would not be in a hurry to start the machine preferring to vacuum it with fresh oil every day for a week . Make sure you get the compressors as warm as possible even adding a couple of CCH's extra or a blow torch. Hopefully the unit is internal and will be at room temp in any case..

monkey spanners
27-04-2014, 06:49 PM
I think you will need to do more vacuuming, at least until you get a good vacuum level on a micron gauge.

I did a start up on a factory reconed system yesterday and it took four oil changes in the pump to get it dry and i'm assuming it had no free water in it.

Another system i dried out,




This one i kept changing the vac oil after the vacuum level stopped dropping, worked out about every 30 minutes or so! took a day of the just to dry out the evaporator, plus i changed the compressor oil and fitted some big core driers.

27-04-2014, 07:42 PM
Thanks for your input gents, I think I will take a load of vac pump oil with me on Monday. Have a torr gauge on so I will see where it's at Monday morning. Have all the crankcase heaters on and the heat pump is located in a very hot boiler room under the pool so this is in my favour.

monkey spanners
27-04-2014, 08:07 PM
Good luck! Keep us posted with the progress :)

28-04-2014, 09:10 AM
The oil was cloudy but didn't seem to be diluted... I haven't tested yet but suspect there will be a lot of acid present.

I have let the company I'm working for know the situation, and on site maintenance but I am really hoping that everything runs up ok on Monday! Have spent a lot of time on this now so hoping for a good outcome!
4 compressors, one heat exchanger with 4 circuits. What is the gas charge weight and suction line size to each compressor?
Some flushing solutions are a right bugger to remove completely afterwards. Are there oil separators?
I would initially run just one compressor with a minimal gas charge and check the compressor oil glass for any signs of discolouration and be ready to hit the shut down. You said: "I poured enough water to fill a bucket from the liquid receiver!" So this system has a common receiver. Now it might have internal surface rust.

28-04-2014, 10:06 AM
Solid core suction line driers. Saved my ass numerous times on seriously contaminated systems after flushing.

28-04-2014, 04:17 PM
Well... Arrived this morning and found that my vac pump was still working! Good start! Oil however was worst I have ever seen! (I will post picture shortly). Despite the knackered oil, the torr gauge was reading 2 torr, which was better than I expected to be honest! Isolated the pump and vacuum did not rise so we are making progress.

I did not attempt to run anything today, instead went out and picked up gallons of vac pump oil and continued vaccing! Several oil changes throughout the day and we are now down to 0.9 torr and pump oil is finally staying clear!

Unfortunately I am not going to get the opportunity to see this one through! I have handed the job over to the companies own engineers today as they have their own labour available this week.

Bit gutted, that I can't stay on to finish, but they are pleased with everything I've done so far so that's the main thing! I know the engineer who is taking it on so he will keep me informed and I will update you...

I have advised that they continue to vac overnight and they have ordered solid suction driers to go in.

I left 3 comps disconnected from contactors so they will try running with one to test.

Thanks for all your input gents, all much appreciated and very helpful. Hopefully this poorly heat pump will live to pump some more heat.....

28-04-2014, 04:19 PM


Vac pump oil after weekend run...

28-04-2014, 06:54 PM
It's amazing to see the diffrence on the oil in the vac pump vs normal use on non contaminated systems.
Thanks for the update.

28-04-2014, 08:02 PM
the last big water contamination took 2 weeks to dry sufficiently for me to feel confident to run the system

still no bad thing they have took it back on as they can hold the responsibility..:)

29-04-2014, 11:50 AM


Vac pump oil after weekend run...
Had to turn into a Fruit Bat to view those pics:D

05-05-2014, 07:18 PM
Had to turn into a Fruit Bat to view those pics:D

I thought you were upside down anyway in aus? The fruit bats are the only ones the right way up!

05-05-2014, 07:21 PM
Last I heard, the guys who took over on this attempted to run and expansion valve instantly blocked with moisture. Back on vac! Will update as soon as I know more.