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What conditions could/would/should create this HIGH HEAD PRESS scenario?? Could the sump at the h2o tower be low on water??ln my past life I have observed a Vortex of water, in the sump just where cooled h2o is entering the pipe going to the suction side of the pump. The Vortex action would allow air to enter with the water.. this event could be created by many things....too much bleed off? Not enough make up? Something was sized improperly I believe you had written where this system had once been a CLOSED LOOP and now it is an OPEN LOOP? Do closed loop cooling systems require HPC water valves when engineered and ballanced properly? I don't know? Good analysis, I like the way you think!


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Originally Posted by Tommy knocker

Ok so we can throw the subcooling out. Could you water regulating valve be hanging up?

The head pressure spikes up to at least 325 I believe that you have seen on your guage yourself correct? With that information alone we know we have a problem with the condenser, be it flow or HPC there is a problem rite there. No need to try and attach that problem to any other symptom. Sometimes we gotta attack one issue at a time. Correct the problem you know you have and see what's left and then attack that. You cleaned the coil and seem confident your flow is good. The only way that head runs up that high every once in awhile, at your guage, is a change in the water flow through that condenser. Would you agree with that if there were no other symptoms?

Lol, no prob.

Originally Posted by Isaac3384

In the morning, the loop temp was cold, but as the day goes on, the loop temp warms up. I'm pretty sure I posted that in another post. Maybe not those exact numbers, but I stated as the entering water gets warmer, the temp difference looks more normal.

Ok. Cooling tower or the like. For some reason I got city water in my head. My bad.

In the morning, the loop temp was cold, but as the day goes on, the loop temp warms up. I'm pretty sure I posted that in another post. Maybe not those exact numbers, but I stated as the entering water gets warmer, the temp difference looks more normal.

Where did the 85 degree entering water come from? Thought you had 60 degree entering water.

Originally Posted by Isaac3384

You're forgetting about the head pressure control...restricts the water flow to maintain head pressure...

As the entering water temp increases, the temp difference decreases...at 85 degree entering water, we have approx a 10-12 degree split...

30* pick up is really high, sounds as if you are not getting enough flow. this would also cause your high pressure due to not getting the proper cooling in condenser. Have you tried descaler in condenser water loop.

I never heard of the vasoline trick. Sounds kinky.

Put a glob of vasoline on the top of the entering water line about 6" from Cond. and run it. If its still there after it trips hot water is not the problem look at your regulating valve. BTW what is your HP cut out set at?

You're forgetting about the head pressure control...restricts the water flow to maintain head pressure...

Fair enough, but i do have a problem with the entering water temp at 60 and the leaving water temp at 90. To me that seems like a very large temperature rise across the condenser, usually should only be around 10 degrees.

Most of the dirt/debris has been caught by the inlet strainers upstream of the pump. There are no hoses; the unit is all hard piped on the water side the debris that was cleaned out of the condenser when I did the acid cleaning appeared to be slimy in texture. There was some sandy sediment that came out of the lines that made it past the inlet strainers, but nothing that could potentially clog the lines. The pressure drop across the condenser is approx. 10# with 60* ent. water and 90* leaving water. I believe I posted all of these numbers in my original post. According to my flow meter, we are moving approx. 7.6gpm. The unit requires 3gpm/ton, and this is only a 1.5 ton unit (quick math tells me that it should only need 4.5 gpm).

If the system has just been recently changed to an open loop system within the last year and if there has been a dirt/debrie issue until just recently it is making me lean more towards a water flow issue/blockage. This may be a stupid question but have you checked the water hoses going into the unit? I have seen some units before where the hoses get rocks and pebels stuck in them some times causing a restriction before. Did you measure the flow across the condenser yet? I am sorry for possing the question again but I may have missed it in a post you have already put up. .

Are you referring to when the system is charged and we have the 'pumpdown' symptom, or when the system is empty and I'm pulling a vac prior to charge?

Hey, I dont mean to jump in at the end here, but I was wondering how long it takes for your system to pull into a vacuum?

Juice, the whole building has been a closed loop system until recently (within the last year or so). They swapped out the towers and made it an open loop system. To the best of my knowledge, there hasn't been a dirt/debris issue until recently. The debris I cleaned out of the strainers was a slimy buildup, along with some sandy material. The condenser has been acid cleaned, and the only debris that was found appeared to be the same slimy debris that was found in the strainers.

The water piping is all done correctly, our head pressure control valve works properly and is installed properly. There are so few components in this system that it shouldn't be this difficult to figure out.

Food for thought!, What happens or would happen in "your" h2o circuit if the direction of WATER flow were reversed????that is to say "cold h2o piped to the outlet and return/line piped to the inlet. .I once had a simulare experience on a closed loop system where Heat pumps were used through-out a 3 story complex.....my predecessor had R & R'ed a unit and had inadvertently crossed the inlet and outlet flexable H2O lines comming to the Xchanger of the unit. With compressor running ...The hot gas went into the cold "water bath" making h2o even warmer then the condensed refrigerant passed thru the warm/and some times hot h2o (depending on the season) .just remembering "IN THE BOTTOM and OUT THE TOP" heat Xchangers...I don't recall the exact symptoms my client had, but I remember "it didn't work so good" "low capacity'' ''tripping on hi head" etc.etc!! LOL

''Another One Bites The Dust"
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For sure sounds like you got 2 different problems, you say that the unit is rated for 3.5gpm and you are capable of providing 7.6gpm but have you actually put a flow meter across the condenser to check and see what your actually getting? If not, I think that's the first thing you should do to confirm this, also have you tried to acid flush the condenser with descaler I have seen them plenty of times where they begin to get plugged up over time. You did mention that at the beginning you had cleaned some strainers from the pumps. Maybe the dirt had been running throughout the system long before you ever got there.

Originally Posted by Isaac3384

I highly doubt it. Granted, this would cause a high head pressure, but this still doesn't explain the bypassing on a new compressor without it showing up on the gauge port that is only a mere 6" down stream.

You did see it I thought. "It reached 325 before I shut it down". You are assuming 400 is where the compressor will bypass. It may be lower. I don't know what it is either but you could call and ask. Your water regulating valve should modulate to maintain 90-100 SCT and it should be steady. The way it's running up and down it would seem either the flow is changing or you are getting shots of hot water.