Pitless o ring replacement

[Adkroot]

Could it possibly be as difficult as it seems to find a replacement pitless o ring? My plumbing supplier - a major supply in the nearest city sold me my harvard pitless 14 years ago and has no replacement o rings for it. Their suggestion is to install a whole new pitless! My pitless is too deep to even humorously entertain this. The very few suppliers of pitless o rings I find online also have limited replacement sizes and the shipping cost is a joke that will likely, inevitably be on me. Regular o rings don't do the trick, as I've learned but that hasn't stopped the guys at plumbing supply counters to try to sell them to me.
Am I missing something here?

 

[Reach4]

Early while searching I suspececd Harvard pitless adapters came to be Dicken brand. However I am not thinking that now.

http://www.discountplumbingoutlet.com/dickens-jr-s-10-1-pitless-adaptor-952156-lead-free/ has this image:

I think that that site just used the wrong photo.

Regular o rings don't do the trick, as I've learned but that hasn't stopped the guys at plumbing supply counters to try to sell them to me.

Learned how? Does the old o-ring have a round cross section, or is it some other shape?

 

[Sponsor]

 

[Cacher_Chick]

You can get a wide selection of o-ring sizes at any decent home center or auto parts store. Don't overthink it.

 

[Valveman]

Regular o rings don't do the trick

I use a an o-ring kit. Just choose one a little small and stretch it to make it fit. If it is large enough to drop right in it usually gets pinched when you slide the foot in the shoe.

 

[Adkroot]

I found the size I need at a plumbing supply yesterday. The issue with regular o rings is that the material isn't the same - an o ring for a pitless is a good bit tougher. Regular o rings, as I discovered, have little tolerance for even the slightest of misalignment and if the diameter is even slightly off they'll easily tear. Anyway, I bought a replacement and an extra.

 

[Valveman]

Most o-rings come in either 70 or more stiff 90 durometer. I have always used the regular 70 durometer 0-rings that come in the kits.

 

[Don H]

My well has a Harvard PT800 1" pitiless adapter (from the original receipt). Just like the OP, I went to the plumbing supply house that sold me the adapter 32 years ago and asked for a replacement O-ring. They told me that they no longer carry that brand (thinks they went out of business) and handed me an O-ring from a box labeled 1" Pitless O Rings and said it "should work".

Before I pull the pump up I'd like to be reasonably sure I have the right O-ring. The O-ring is:
Blue in color and rather stiff.
Measures about .20 thick, 1.78 OD, 1.35 ID (as measured with cheap HF calipers).

I figure pick the old one out, make sure the groove is clean, the new one should need to be stretched a little to fit. Use plumber's grease on mating surfaces and the O ring.

Can anyone confirm this is the correct O-ring?
Is there anything else I should know about installing the O ring?

 

[Reach4]

Is there anything else I should know about installing the O ring?

Silicone grease.

 

[Don H]

Silicone grease instead of plumbers grease?

 

[Reach4]

Silicone grease instead of plumbers grease?

Yes. Plumber's grease is usually petroleum-based.

https://www.danco.com/product/0-5-oz-silicone-faucet-grease/ Danco 88693 would be good.
I use Molykote 111 for my o-ring and seal use. A little goes a long way. 5.3 ounces can be a lifetime supply. It has a really long shelf life after opening. Release compound is similar but lower viscosity. A pro might tend toward that. It is faster. I like the slower and higher viscosity, but both ways are good. I wear nitrile gloves to apply. I am not a pro.

Try this search is a search engine:
"Not for use on rubber or synthetic O-rings"

 

[Don H]

Thanks, I didn't know that. My plumbing supply house should have it.

 

[Don H]

I ordered an O-ring for the Harvard PT800 from FW Webb Plumbing https://ordering.fwwebb.com/woitem/92515
This O ring was an exact match to the original one.

 

[Don H]

Is the groove cut in the pump side of a Pitless adapter that accepts the o-ring round or square in cross section?

I understand that some Pitless Adapters many years ago had leather rings to seal between the two haves. This leather ring seal supposedly had a square cross section. I'm assuming those adapters also had a square (cross section) grove cut in it to accept the square leather ring. My Pitless has a square cut groove.

I had my pump serviced one time by the original well driller for a check valve. I'm wondering if they replaced a square (cross section) leather seal with a rubber round (cross section) o ring. This may be the problem with why it's leaking.

The specific adapter in question is the 1" Harvard PT800 which is about 30 years old.

 

[Reach4]

 

[LLigetfa]

Is the groove cut in the pump side of a Pitless adapter that accepts the o-ring round or square in cross section?

Forget about the old "round peg in a square hole" analogies... it does not apply to O-rings. Grooves cut in shafts or in pillow blocks for O-rings are square, not round. The O-ring deforms and seals where it contacts the flat surfaces.

 

[Don H]

Thanks!