problems in high ambient

[philjd26]

hi

its not often we get nice weather here but the last couple o days have been belters and guess what? i am on bleedin call...anyway have 2 x 25 kw dx coolers condensers which are installed in a tight little compound below ground level and have trouble with short cycling when it hottish out...i.e trips on h/p..

the client is aware of this problem for a long time, however to it would be a job and a half to move condensers to a suitable location...might be a bit ify but i was thinking of installing a water supply spraying on to coils operated by a solinoid if the head pressure where to get to a certain pressure has anyone ever done anything like this or can anyone see any problems with it?

rgrds phil

[taz24]

hi

its not often we get nice weather here but the last couple o days have been belters and guess what? i am on bleedin call...anyway have 2 x 25 kw dx coolers condensers which are installed in a tight little compound below ground level and have trouble with short cycling when it hottish out...i.e trips on h/p..

the client is aware of this problem for a long time, however to it would be a job and a half to move condensers to a suitable location...might be a bit ify but i was thinking of installing a water supply spraying on to coils operated by a solinoid if the head pressure where to get to a certain pressure has anyone ever done anything like this or can anyone see any problems with it?

rgrds phil

I have done it in the past but waste water will be an issue, make sure no water can get on any electrics and it will rot the cecondenser faster.
Make the customer aware of the possible issues to cover yourself.

taz.

[chemi-cool]

If you want to solve the problem for good, put new condensers in with more than one fan and HP to control the head pressure.

Playing with sprinklers is for children.....


Chemi

[US Iceman]

...condensers which are installed in a tight little compound below ground level and have trouble with short cycling when it hottish out...

I'm assuming you mean short cycling of the air flow for the condensers. If that is the case the only way to solve the problem is to move the condenser up to a location where the airflow around the condensers is unimpeded with no adjacent obstructions that can cause the air to recirculate back into the condensers.

Architects probably specified this so that those nasty condensers did not offend the aesthetics of the facility.

[The Viking]

Playing with sprinklers is for children.....

And ladies in wet T-shirts...Mmmmm.


BTW, Water sprayers on thermostats or pressure switches is an tried and tested method of lowering the HP. Not much different than a rainfall.
Yes, the coils lifespan might be affected and yes, electrical stuff might suffer but we are talking about kit designed for outdoor life.

If the water is hard, then filtration might be beneficial (BUT NOT SALT BASED WATER SOFTENERS)

There are also purpose made kits to buy with "proper" orifices and pumps, I believe that either HRP or D&W sells them.

[philjd26]

If you want to solve the problem for good, put new condensers in with more than one fan and HP to control the head pressure.

Playing with sprinklers is for children.....


Chemi

i agree but client has little space and funds to play with...as i said this only happens in high ambient condition which is not very often...another idea i have is ducting off condensers?

[philjd26]

And ladies in wet T-shirts...Mmmmm.


BTW, Water sprayers on thermostats or pressure switches is an tried and tested method of lowering the HP. Not much different than a rainfall.
Yes, the coils lifespan might be affected and yes, electrical stuff might suffer but we are talking about kit designed for outdoor life.

If the water is hard, then filtration might be beneficial (BUT NOT SALT BASED WATER SOFTENERS)

There are also purpose made kits to buy with "proper" orifices and pumps, I believe that either HRP or D&W sells them.

cheers viking

il have look into it,...

[US Iceman]

...another idea i have is ducting off condensers?

If you install discharge ducts on the fans the increase static pressure of the ducts will reduce the air volume delivered by the fans. However, if you can up-size the fan motors you might be able to compensate for this.

Another issue might be anchoring the ducts so the wind doesn't blow them away.

[frank]

i agree but client has little space and funds to play with...

The best option then may be to take what little money he has down to the trick shop and buy a MAGIC WAND
Some problems are simple to correct, others cost money. I think this problem falls into the latter.

[superswill]

we had just the same problem with four mitsubishi unit installed in a shopping setting basement,after the client weighted up the service call out charges that during the summer months were becoming far to frequent,and in sort the only thing we could do was to hose the coils down, against the cost of moving them it didnt take too long before would had a brand new VFV system on the roof

[Electrocoolman]

Ducting might work providing it is in the form of a large box section on top of the condensing unit to in effect 'baffle' the airflow, and discharge the exhaust above ground level.


Can you post any pictures? How far below ground level are these units?

[chemi-cool]

How about water cooled condenser and a cooling tower??



Chemi