What Are the Advantages, Disadvantages of Pitless Adapter Tanks?
I’ve written several columns on these unique pitlesses known as pitless adapter tanks. I also know that some of you readers — several of whom are good friends of mine — are going to think I need to get a mental tune-up as these PATs, as they are often referred to, had and have no advantages whatsoever. I must respectfully disagree and will now list what I consider advantages of this type of adapter.
One of the first advantages that comes to mind is that a well and pump installation equipped with one of these is absolutely silent. I have a number of customers who object to the hum that most submersible pumps make, even if they are very quiet when compared to other types of pumps. About the only sound a PAT job makes is the slight click made when the pressure switch either opens or closes. If this switch was mounted on the air tube of the tank, no sound was heard inside the building the system served. It was almost like being connected to a municipal supply.
Another advantage was that, being buried in the ground, these tanks did not sweat. The summers in Michigan can get pretty warm and rather humid, not as humid as you folks in the Carolinas or the deep South would experience, but our air is plenty moist. A regular pressure tank in a basement will sweat something fierce. I was once called to service an installation that I had made and the owner swore up and down that some pipe connections were leaking. This was mid-summer and the tank was sweating terribly, with the condensation forming a pretty good-sized pool near the tank. With the tank buried in the ground, this was not a problem.
Another advantage these PATs had was that we could install a relatively large tank. A larger tank meant a longer run time for the pump and, usually, longer pump life. I think the largest PAT I ever installed on a residential job was 145 gallons, and I did several of these. A regular 120-gallon or 220-gallon inside tank would have been cumbersome, would take up a lot of basement space and would really cause condensation to appear. Readers, you have to remember that we are talking about the days when big water meant a big pump with a big tank and big water lines, unlike some of the more sophisticated systems we have today.
Actually, in some installations there was no room for a pressure tank inside anywhere. We don’t have a lot of houses built on slabs here in Michigan, but we have quite a number with crawl spaces and some of these are really way too small, in fact dangerous, to enter. For an installation on a residence like this or a mobile home with a crawl space, the PAT system was made to order. We also encounter animal facilities, barns and etc. that are on a slab and sometimes have just earth floors and are not heated in any way. For one of these jobs, a PAT system and a freeze-proof hydrant filled the bill. I made quite a number of these installations and they worked just fine. Not incidentally, in our state of Michigan there are only a few freeze-proof hydrants that are approved by our DEQ or our local health departments. The typical drain back and empty to earth hydrant is not approved and no amount of check valves, backflow preventers, etc. will make them legal.
As you can see, I believe these PATs did have several advantages. They required periodic air charges, unlike our modern captive air tanks, but if the owners or service people kept them properly charged they were a reliable system.
As to disadvantages, these PAT systems really had only one, and it was a huge one. The early PATs we installed had ⅛-inch carbon steel construction. Around the mid 1960s we were required to go to ¼-inch steel construction. Being carbon steel, these tanks would eventually rust out and start to leak. I drilled many, many 4-inch wells and the pipe we used for casing was .237-inch carbon steel and many of these wells, whether drilled by me or others, lasted 50, 60, 75 years. Why tanks made of the same material sometimes only lasted 10 years, while others were still going after 30 years is a question I have never gotten a decent answer to.
I will admit that when these PAT systems began to leak, the pump man had one heck of a job on his hands. They didn’t start to leak one day and were replaced the next, but had been leaking for weeks, months, maybe even years. If the leak was in a convenient place you could possibly use a tank patch or weld over the leaking spot, but some of the leaks were areas that were impossible to patch or weld. So the answer then was to replace the tank. For this, you needed a whole lot of equipment and quite a few people.
First of all, you had to pull the pump and if the original installer had not lubricated the O rings on the spool this could be a real blinger. So you needed a pump hoist or perhaps a well rig. Next, you needed a backhoe or several very strong, very hearty fellows equipped with shovels. As the excavation was made, many times it filled with water — we have a lot of clay ground in Michigan and this ground would be waterlogged, making it soppy, sticky and slippery. I was usually the “pit man” on replacements we made and, believe me, it was not fun. It was also a good idea to have a ditch pump on standby to pump out the excavation and probably a pickup to go back to the supply house or your shop to get extra parts, as no two tanks ever seemed to match up exactly.
As you can see, replacement of these PATs was a real process. We often joked that if the customers would stand the price and you had about 200 of these installations in the ground, you would not need to get any more work since, by the time you replaced number 200, number 1 would be ready for replacement again. This is like the folks who paint the Mackinaw Bridge in northern Michigan. This is a suspension bridge that is over 5 miles long. When the paint crew gets to one end, it is time to go back and start again. The bridge has been standing since 1957 and they do a good job, as it looks like new. But they don’t have to look for other work.
With the coming of captive air tanks, VFDs and other more modern pump accessories, these pitless adapter tanks disappeared from the industry, at least as far as I know. If I am wrong about this, I would hope any of you readers who know differently will inform me. So, I end my writing on a rather unique product that did solve some problems and created some too.
As I write this in the middle of May we have had plenty of rain here in southern Michigan, so my grass is nice and green and I’m keeping both my tractors loosened up by usage — not just as ornaments. Lately we have had several nights where it got to near or below freezing, and last weekend we had snow flurries. I guess summer will get here eventually, and I bet that when it does it will be blazing hot. Until next time, work hard, work safe and take pleasure in the fact that you are part of a great industry.
For more John Schmitt columns, visit www.nationaldriller.com/schmitt.