Water source Heat pump question

C

Cursitti

Member
Location
Maryland
Occupation
Journeyman Electrician
All i have a job i just started on with a hvac contractor who is replacing all existing equipment and doing a total repipe. My job is pretty simple just disconnect and reconnect what’s there. Last night we started on a floor that has roughly 50 water source heat pumps. I have drawings from the original build back in 1997. These drawings show two water source heat pumps on one circuit with a 15 amp two pole toggle switch as a disconnecting means. But for the overcurrent protection, they have a two pole 30. Now as I’ve been disconnecting these switches I’ve been finding that they’re 20 amp which is totally fine. But what’s concerning me is that they are on a 30 amp circuit and it’s not being fused down to 15 A as the manufacture nameplate states MOCP 15. I’m just asking for advice on what you guys would do in this situation as I’m only supposed to be disconnecting and reconnecting and I don’t think there is enough money in the job nor does the contractor want us to start Redoing a lot of work. I’ve caught a couple things recently on this job as far as changing out motor starters with VFD‘s and upsizing breakers for the input current. But this is a pretty big situation as there is three floors and there’s about 50 water source heat pumps per floor. Any advice helps.
 
Do the units show a max overcurrent protection and type ??
 
I agree with adding the fused disconnects.

Just wondering if you mounted a 15 amp (actually a 0-30A) two pole fuse block in each unit with a 30 amp two pole toggle switch would that be legal?
 
Cursitti said:
All i have a job i just started on with a hvac contractor who is replacing all existing equipment and doing a total repipe. My job is pretty simple just disconnect and reconnect what’s there. Last night we started on a floor that has roughly 50 water source heat pumps. I have drawings from the original build back in 1997. These drawings show two water source heat pumps on one circuit with a 15 amp two pole toggle switch as a disconnecting means. But for the overcurrent protection, they have a two pole 30. Now as I’ve been disconnecting these switches I’ve been finding that they’re 20 amp which is totally fine. But what’s concerning me is that they are on a 30 amp circuit and it’s not being fused down to 15 A as the manufacture nameplate states MOCP 15. I’m just asking for advice on what you guys would do in this situation as I’m only supposed to be disconnecting and reconnecting and I don’t think there is enough money in the job nor does the contractor want us to start Redoing a lot of work. I’ve caught a couple things recently on this job as far as changing out motor starters with VFD‘s and upsizing breakers for the input current. But this is a pretty big situation as there is three floors and there’s about 50 water source heat pumps per floor. Any advice helps.
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Will there by any inspections required for the work you’re doing?
 
Sorry all for the delayed response this is a night job and i have very limited access to phone service. Some background on this job is it’s at a university and all of these heat pumps are inside of classrooms. The first floor I did all of the switches were located on the inside of the heat pumps. They came up through a poke through along with water lines all we did was replace the switch and reconnect to new heat pump. On this floor, the switches were surface mounted with conduit on the walls. this is when I started noticing the problem and I got my hands on the original drawings. Tonight, as we are working, I investigated some more and found the previous contractor ran #10 wire from the breaker to a local junction box and then pigtailed off with #12 to each of the two units. Then it hit a 2 pole 20amp switch and then went into the unit. I let my supervisor know my concerns and it doesn’t sound like the university would want disconnects mounted on the walls as there is students that are curious and would eventually mess with them Even the little pull out ones so they want to keep the two pole switches along with a lockout cover so nobody can turn the unit on and off. My question is could I use in-line fuses after the two pole switch and fuse that down to 15 amp?

I’m going to write an email this morning about my concerns and see if the university would like to fix this or leave it. Dealing with them in the past they usually let things fall on deaf ears. I appreciate the input thus far. This is a year long job with fitters and I’m seeing now its more then just disconnect and reconnect. So I’m now trying to stay on this. I haven’t been told of inspections but another contractor is doing some panel upgrades throughout the building so I’m thinking that will be inspected. Please see attached photo of 97’ drawings for typical heat pump wiring. In which the contractor didn’t follow using #10 to the switch.
 
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