Bypassing Hi/Low pressure cut offs

[hurtinhvac]

We should all know better when it comes to bypassing safety switches in heat except for on site diagnostics. Or motor overloads.

What about high and low pressure cut offs in cooling when the accompanying pressures are normal and the cut offs are tripping?

I guess another way to pose the question would be this: Is there any condition that would trip a cut off that you would not be able to detect by system pressures?


Appreciate any consideration,

h

[dudeabides]

It's tempting to do but I don't think it's worth jumping one out. I don't like to have "what if's" bouncing around my head when I'm home. Things could look ok when you're there, but anything can happen. Say you jump out the the pressure switch that's open even though the systems running @ 250. Then you leave, and the condenser fan dies. Uh-oh. Not worth the risk.

[hurtinhvac]

It's tempting to do but I don't think it's worth jumping one out. I don't like to have "what if's" bouncing around my head when I'm home. Things could look ok when you're there, but anything can happen. Say you jump out the the pressure switch that's open even though the systems running @ 250. Then you leave, and the condenser fan dies. Uh-oh. Not worth the risk.

Good point.

[jburchstead]

They sell low end equipment without those safety switches, but I agree with the other posters. You need to restore the customer's equipment to its normal working condition. I have done it to give some temporary relief until I could I could get back and do it right.

[coolerik]

really, whats the worst thing that could happen..comp will trip overload or the breaker...worse case your comp will plow the internall relief or if its a bigger system blow the relief and there goes a few hundred lbs.....doubt its gonna hurt anyone not like jumpin a limit on a gas fired appliance
still not reccomended by me, but i doubt its gonna hurt anyone

[ORV]

It's tempting to do but I don't think it's worth jumping one out. I don't like to have "what if's" bouncing around my head when I'm home. Things could look ok when you're there, but anything can happen. Say you jump out the the pressure switch that's open even though the systems running @ 250. Then you leave, and the condenser fan dies. Uh-oh. Not worth the risk.

I found one like this yesterday. Tripping on high pressure. Freon charge looked great. Amp draw was 1.6 on condensor fan motor rated at .9. Cap was good. Motor coming in Monday.

[hurtinhvac]

I found one like this yesterday. Tripping on high pressure. Freon charge looked great. Amp draw was 1.6 on condensor fan motor rated at .9. Cap was good. Motor coming in Monday.

CF motor failing and the high side wasn't elevated?

[timebuilder]

Yesterday, I had my first "no ac" call of the season.

Compressor not running. Good standing pressure, but low side cutout open.
I jumped it out just long enough to find out why it failed. Poor aiflow has been causing the unit to cycle on the switch, until it gave up. In commercial, we quote all proposed repairs first, a process that takes an aproval from the store corporate.

Leaving that switch out and running the unit would not have been a professional repair.

[Chris_Worthington]

How long does it take to add a tee and another switch anyways? What about 10 minutes? The cost for equals? not much.....

[y7turbo]

Leaving that switch out and running the unit would not have been a professional repair.

Bypassing the switch and giving them cooling also gives the cheap customers a reason not to replace the switch, because its "working" now..

[hurtinhvac]

How long does it take to add a tee and another switch anyways? What about 10 minutes? The cost for equals? not much.....

In case you are after hours and didn't have one on the truck.

May I ask what "tee" you refer to? I thought it was a simple matter of a threaded/schrader fitting?

[Chris_Worthington]

In case you are after hours and didn't have one on the truck.

May I ask what "tee" you refer to? I thought it was a simple matter of a threaded/schrader fitting?

Assuming the old has no schrader core, add an access tee with a core depressor, attach switch and call it done

As others have said that is a call you need to make, supply houses are generally open the next day here

[ar_hvac_man]

In case you are after hours and didn't have one on the truck.

May I ask what "tee" you refer to? I thought it was a simple matter of a threaded/schrader fitting?

Adding a tee to the low or high side will allow you to add a new pressure switch without losing or having to recover any refrigerant.

[dlove]

really, whats the worst thing that could happen..comp will trip overload or the breaker...worse case your comp will plow the internall relief or if its a bigger system blow the relief and there goes a few hundred lbs.....doubt its gonna hurt anyone not like jumpin a limit on a gas fired appliance
still not reccomended by me, but i doubt its gonna hurt anyone

maybe not physically hurt someone, but if a service provider jump out a safety and my unit blew up. That vendor would buy my a new unit. regardless of the age of the unit, the hurt comes from not having a job or a bad rep.

My advice, record everything, do it right and inform the customer, if you cant fix it before you leave lock it out or pull the fuses

[beenthere]

How long does it take to add a tee and another switch anyways? What about 10 minutes? The cost for equals? not much.....

And the strange thing is. The customer will pay you to do that.

[ORV]

CF motor failing and the high side wasn't elevated?

Fan was eventually going out on overload. The maintenance guy would notice it and reset high pressure and walk away. When I pulled the motor all of the oil was leaked our of it.

[hurtinhvac]

Assuming the old has no schrader core, add an access tee with a core depressor, attach switch and call it done

As others have said that is a call you need to make, supply houses are generally open the next day here

No schrader? Holy crap...this is why it pays to hang out here!

Anyone have a picture of this tee handy?

[Chris_Worthington]

No schrader? Holy crap...this is why it pays to hang out here!

Anyone have a picture of this tee handy?

Here ya be http://www.rsd.net/search/item.php?i...=JB+A31851-100

[hurtinhvac]

Here ya be http://www.rsd.net/search/item.php?i...=JB+A31851-100

Thank you.

[TechmanTerry]

I use them so often that I carry 8 (2 of 4 diff types) of them in my regular tool box.