SpacePak ESP-D capacitor replacement

Bucky

Hi guys, my trusty 17 year old SpacePak stopped working yesterday. I use if for "aux" heat on chilly days between heating and cooling season once I shut off the radiant floors. So I have some time before cooling season kicks in, so I'm going to troubleshoot why the fan stopped. Hoping either the relay or the capacitor. Relay is easy enough- it's right up front. However, I don't know where the fan capacitor is. I don't want to start disassembling stuff in hopes of finding it because it's in a very tight crawlspace- I want to have a good idea what I'm after. So the question is, does anyone know the whereabouts of the fan capacitor in a SpacePak ESP-D (ESP-3642D to be specific) and what I have to tear about to get at it? Thanks!

mattmia2

I don't know about space pak specifically but they are usually mounted to the blower housing or the motor itself. Sticking a phone in and taking some pictures might help. I'd check the play in the bearings and remove the blower wheel and scrub it out with some detergent and a brush while I was in there.

hot_rod

Could it be an ECM blower motor?

Bucky

No, the wiring diagram definitely shows a capacitor- and now that I look at the spec sheet, it even calls out "PSC" for motor type. As per Matt's comment: I assume to do this I would remove the outlet ducting and that's where I'd stick the phone in in order to look at the motor?

mattmia2

There isn't a blower compartment door that comes off? I've never looked closely at a space pak air handler, just know it is a high velocity system.

Bucky

I guess #11 is it? Listed as "Access Panel".

mattmia2

Looks that way. Is that a small access panel on the top?

Bucky

No, that is an alternate location for the supply air outlet.
Looks like fortunately this is readily accessible in this crammed crawlspace. I imagine the installers used some forethought in the way they oriented this.

HVACNUT

That junction box shows a terminal block, transformer, and heat sequencer. 
Pop off the door with the Space Pak sticker. Its probably attached to the blower housing or motor frame.

Bucky

Progress Report: Got in there, but didn't have the proper nut driver to unfasten the capacitor to inspect it to determine the rating. Nor did I have an inspection mirror. I'll have to get back in there. I did confirm that the circuit for the fan relay is getting 24v when the fan is switched on. I didn't try to confirm if the switched side of the fan relay was showing 120v though- I've got to figure out some way to be able to work with 2 hands in the crawlspace. I'm currently limited to lying on my side and working with the arm that isn't under me. (I can't sit cross legged due to fake knees, and even if I could I'm not sure I would have the clearance anyway). There is a buzz in the control block when power is on (it's constant, so it's not the relay I don't think- it doesn't change when the fan circuit is energized). Oh well, little bits of progress is better than none I guess!

mattmia2

An offset screwdriver would get you there too. You want to loosen that screw on the clamp and slide the cap out because that bolt that holds the bracket on goes through the motor to a nut on the other side and would probably be more complicated to work on in situ. If you look there are is probably a bolt or 2 that comes out and releases the blower assembly and you can pull the whole thing out. Is the buzz only from the contactor or is it at the motor too? If it is only at the contactor it probably isn't the cap. Some leads with clips would help a lot with reading voltages.

Bucky

Thanks for the tips! Yeah, I was going to remove the entire bracket- but knowing this now I will loosen the clamp if necessary. So if I undo the four bolts surrounding the motor (the diagram upthread appears to be accurate) I can slide the squirrel cage to the right and pull the whole thing out (assuming there's enough wiring slack)? And yes, it came to me last night- just put an alligator clip on the negative pole of my meter and I can clip that to the frame and then probe the relay/contactor one-handed. When I was in there in the fall planning my control re-wiring, I didn't notice any buzzing. So maybe it is the contactor that's gone south? I imagine the meter will give me the definitive answer there. Heading out of town on business for several days, so I won't get back in there until late next week- fortunately the spring weather gives me a little runway to figure this out.

mattmia2

I think the whole motor and blower housing have to come out as an assembly. The blower wheel won't clear the blower housing if you unmount just the motor and it would be difficult to get the blower wheel realigned inside the air handler and there may be another bearing on the other side of the blower housing to support the shaft. The diagram doesn't seem to show how it is mounted but many slide in to some sort of rails and are secured with a couple bolts.

Are you sure there is 120v up to the air handler at all?

Bucky

Into the Air *Handler* itself? Yes. The transformer is definitely getting power, and that's fed from the same 120v leg that feeds the relay. And interesting (to me, anyway) is that the other 120v leg that goes to the blower motor is unswitched- so it's always getting 120V. I do see that the motor mount also seems to have bolts through the bottom of the assembly- I wonder if that's one piece with the blower housing, so if I removed those six bolts (assuming there's also three on the non-pictured side) the who thing would just slide out? Anyhow, I think before I go there I have to verify whether the relay is passing power through when it's supposed to. The HV connections of the relay are on top, so at least that *should* be simple to determine when I get in there again (and remember to bring an alligator clip!).

Bucky

Well duh, now that I see the picture I took yesterday (I was reaching with my right arm, so my eyes didn't have that view) I imagine the simplest thing is just to use my non-contact voltage detector and see if both legs to the motor are hot...

mattmia2

There might be a door interlock switch you have to defeat with that side panel off to get the blower to operate.

Bucky

Thanks for the heads up! The schematic doesn't show one, and I didn't see one either- but I will definitely give it a closer look on my next visit!!

HVACNUT

If you're trying to pull the whole assembly, remove the 4 bolts from the motor bracket, and of you look at the blower housing you'll see a  ring with 6 screws. Remove the screws and ring. That will clear the fan from the housing.
Outline the motor location and ring with a Sharpie before removal so you know you're lined up right when it goes back in.

Bucky

So to close the loop here, turns out first guess was the right one- it was the capacitor. HVAC buddy was over when I had a hyrdonics problem (both expansion tank and relief valve were shot) and while I was out picking up a new expansion tank he ventured into the crawlspace and replaced the capacitor. I never did ask him how he determined it was the cap- guess I'll have to remember that next time I speak with him.

Thanks for all the help here!!