Combing an Outdoor Coil

[sharp]

Hello - I have hail damage to my outdoor coil on my lennox HP 29 heat pump (3-ton). I have a "coil comb", and was wondering what specific size I should use? The selections are 8, 9 , 10, 12, 14, 15. Any help and advice are appreciated. Thanks much.

[Midwest]

It depends... what the fin count/inch is for your unit. Find a section of fins that isn't damaged and test fit the comb gently. If they are pounded pretty flat, you will certainly have your work cut out for you. Or, do what I did and throw or give the comb away.

I have seen a lot of fin combs in tool boxes and few if anybody seems to use them. Heavily flattened fins are a pain to undo. The best remedy I've found is cheap: a plastic picnic-type knife. You only get to work one fin at a time, but if the flattening is severe it works fairly quickly. IMHO combs are a tool that looks like a great theory, but in real practice they fail to work well on serious flattening. Slight, gentle flattening is another thing. After the plastic knife, you can use a comb for touching up, but I think that's about their limit of use.

[sharp]

Thanks Midwest. The plastic pic-nic knife idea is intriguing. I have (unfortunately) invested $10 in the comb, but will gladly pitch it if the knife proves superior. Again, thanks. -Sharp

[hvaclover]

We train our personnel to use the combs on all badly beaten condensers. It's a real pain but the customer will usually opt for fin straightening before buying a new condenser.

[sharp]

UPDATE: I removed the grill from the outdoor coil and used the picnic knife and the fin comb. Actually, the picnic knife was too broad so surprising, the fin comb on "15" (the smallest comb) worked ok but not perfect. It unflattended the fins but did not restore the coil to perfect condition.

I have to assume that combing out flat spots is preferrable to leaving them flat from an efficiency standpoint? If anyone can tell me how much important keeping the outdoor coil in good shape contributes to efficiency I'd appreciate it. -Sharp

[billva]

airflow.

for heat transfer you need air flow, blocked coils reduce airflow and thus heat transfer. dirty of restrictive filters will do the same.

replace disposable filters monthly.

good luck.