The availability of some refrigeration components can create major issues when repairing a system. Occasionally you may be faced with a dilemma where the component you need is not available, and the customer is in desperate need of getting the system up and running. Recently I ran into a scenario where what I thought would be an easy repair ended up being quite a challenge.
I was called out to repair a fairly large walk-in freezer. It was low on refrigerant, and I was able to locate the leak on the fusible plug on top of the receiver. The fusible plug had not blown out; the leak was on the threads between the tank and a bushing used to connect the fusible plug to the receiver. I first attempted to tighten the bushing to try and repair the leak. Of course, that did not work, and in fact, it made the leak worse.
Luckily, this receiver had a service valve on its inlet and outlet, and I was able to isolate the receiver from the system. After isolating the receiver, I recovered the refrigerant and removed the fusible plug and bushing. Again, I assumed it would simply be a job of cleaning up the threads and using some pipe dope to reconnect the bushing and fusible plug to the receiver. After pressure testing it with nitrogen, it was still leaking and actually seemed to be a little worse.
So what seemed to be a simple repair was turning into a problem. I decided to go and get a new bushing and fusible plug, thinking that would solve the problem. It did not. Then I decided to clean up the receiver threads with a tap, thinking the threads might be the issue. They were not. It was still leaking. So after trying a new bushing and fusible plug and cleaning up the threads on the receiver, I was back where I started.
The next step was to replace the receiver. This system used a vertical receiver, and as a fairly large walk-in, the receiver was also big, with a holding capacity of about 100 pounds of R-404A. I called around to all the wholesalers in the area, and no one had this receiver or anything close in stock. I was told the delivery time on it would be four to six weeks. Now we had an issue.
We considered using a horizontal receiver, but this was an outdoor condensing unit and there was no room to mount that style receiver. Having the walk-in shut down for four to six weeks was not a good option for the customer, so we started to brainstorm ways of solving the problem. I explained the issue to the counter guy at our local wholesaler, and he jokingly suggested we braze the bushing onto the receiver. That joke turned into a potential idea. He suggested we use a 56% silver alloy to bond the brass bushing to the steel receiver.
We returned to the jobsite and tried this repair. We threaded in place the brass bushing and temporarily installed a brass nipple where the 3/8-inch fusible plug would go, and it worked perfectly. After allowing the bushing to cool down naturally, we installed the fusible plug, pressure tested, and with a smile on our faces, found no leaks.
So the next time you are faced with a difficult task, keep at it and leave no stone unturned until you find the solution to the problem. It may not always turn out this successfully, but when it does, it is a very satisfying experience for all.