Can I create a bypass to pressurize heatign supply piping?

Hello all! Another amateur question for my heating system project. I wanted to test all the soldering points before the inspector comes by and I didn't realize that the boiler won't allow any water to pressurize the system without it being turned on but it isn't ready to function yet (Gas is still turned off and venting still needs to be done this weekend). I was thinking of bypassing the recirculator in the boiler by installing a hose on the potable water supply onto the purge/flush hose end shown in the picture below (Either the red/blue isolation valves on the right side of the picture). Then hooking it onto the drain in the bottom left of the picture.

Easy enough to do... but what I'm afraid of is the 60 PSI that my main shoots out. I see no reason why the copper piping shouldn't be able to handle this pressure (I mean... it's made for it afterall...) but there is the air separator and the circulator pump that is normally only subdued to 30 PSI max before the pressure relief lets go. I will leave the shutoff valve off that leads into the boiler so not to pressurize any of the internals. This will allow me to test all the joints and connections up what is left on the hot water supply isolation valve.

An easy way to do it would be to get a double ended garden hose connection and fill the piping throu a drain valve from a spigot from your house. Fill it slowly and keep an eye on the pressure gauge and you won't have the relief valve pop. You could also pressurize with air if you wanted.

Matt30 said:

An easy way to do it would be to get a double ended garden hose connection and fill the piping throu a drain valve from a spigot from your house. Fill it slowly and keep an eye on the pressure gauge and you won't have the relief valve pop. You could also pressurize with air if you wanted.

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The relief valve is before the shutoff valve that I would leave off so it would never hit the relief valve. That is pretty much exactly what I was thinking of doing though. The hose that is hooked up is a washer hose and I would just move it over to the drain valve and hook the other end onto the potable water valves to pressurize the system. I'm just worried that something would break under 60 PSI since the normal max on a heating system is 30 PSI

Well I pressurized it and everything seems ok. The only things I worry about is the internals of the boiler and the circulator pump. The air separator held just find and released the air as it should. So I'm bypassing the circulator for now and I have the isolator valves turned off right before the boiler. I had to cut the pressure down to 50 PSI but I don't think the tenants will notice much of a drop from 60 PSI. I did that because my pressure gauge only works up to 50 PSI.

You will not harm any of the components by introducing them to that low of pressure. No worries!

Well during the test just about every threaded connection had a small leak lol. Been fighting with them tooth and nail. Even ended up soldering the valve spigot to the strainer because no matter how much teflon tape and how much i tightened it down, it would NOT seal. I had it touching both non threaded ends and put about 6-7 spins of teflon it... I'm having a another issue with the strainer where the male end goes into the strainer for the compression fittings continues to leak. I didn't go quite as hard on it as I did with the spigot so I'm going to pull it apart tomorrow and take a look at whats going on. But I might just end up soldering that one too. At least the compression ends are sealing good though.

I'm also having a leak on every threaded fitting near the supply/return lines for the boiler. I don't want to damage the stainless steel fittings that are connected to the boiler so I didn't whack at it too much but it is pretty well on there... I'm running out of ideas on how to fix these leaks without destroying all the fittings.

On top of all this since I put pressure in the system the way I did I ended up getting backflow pressure and now my back flow preventer vent is stuck open... I heard often times debris, solder or teflon can get stuck between the O-Rings so I might just pull it apart to see if that is what happened. Otherwise I have to return that for a replacement.

Ironically all the soldered joints are great lol. I've sealed 1500 PSI hydraulic lines countless times at my job and I can't get these fittings to seal at <30 PSI. I've never soldered in my life, and I only had 2 joints leak in the entire system, both were on the potable water side. Every fitting on the hot water heating side looks good.

Is it possible you may be applying too much heat near the threaded connections? You want to pre-fab as much as possible before you have to solder. And when I solder within 2 feet or so of a threaded connection I always wrap a wet rag around it.

Also, I’m the type of guy who uses both teflon, and a thread sealer on my joints. Knock on wood *taptap* leaks don’t occur often

Matt30 said:

Is it possible you may be applying too much heat near the threaded connections? You want to pre-fab as much as possible before you have to solder. And when I solder within 2 feet or so of a threaded connection I always wrap a wet rag around it.

Also, I’m the type of guy who uses both teflon, and a thread sealer on my joints. Knock on wood *taptap* leaks don’t occur often

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Some of the threads were pretty close to the heat, but the connections that are on the boiler were before heat. I did prefab a lot of things before hand. Only had to solder several joints on the setup itself to make the final connections. There are some threaded connections I don't mind soldering but I can't solder it onto the boilers end fittings. Those two I need to have stop leaking. When you apply thead sealers do you apply it before or after the teflon? I have some special 5 that i heard was really good but I haven't used it yet. I got it to use on union/compression ends if they leaked but they have all been good in my setup.

Put the pipe dope over the teflon tape.

A little of pipe dope after the Teflon, on top.
You are doing something wrong.
43 years of using Teflon (and a touch of dope, just for security) and the only leak I have ever seen is ...none.

I put Teflon and dope on threads and tighten until my channellocks slip, which sometimes is only a quarter of the threads, and they never leak.

breplum said:

A little of pipe dope after the Teflon, on top.
You are doing something wrong.
43 years of using Teflon (and a touch of dope, just for security) and the only leak I have ever seen is ...none.

Click to expand...

I'm not sure what I could be doing wrong since you wrap the teflon in a clockwise manner. By directions your supposed to apply 3 spins of teflon (Although I often times spin it once or twice more especially with the thin stuff), and you tighten it down. I usually try to only tighten it with a 12" pipe wrench but I've been finding the need to use my 24" to ram these threads down in, and even then it doesn't seal. It's NPT to NPT. I never back the threads out. What more is to it... I never tried a teflon and dope combo. I'll try and see what that does for me.

anticlmatic said:

I put Teflon and dope on threads and tighten until my channellocks slip, which sometimes is only a quarter of the threads, and they never leak.

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I did only use my channel locks for the fittings that attach to the boiler. I didn't want to damage the threads coming out from the boiler so I was much cautious about messing up the threads on them. Still leaked.

So far so good with the pipe dope/teflon trick. No leaks. I'm going to leave it pressurized at 30 PSI for a little while longer but I think 15 minutes should've been enough time for it to show signs of leakage.

TomFOhio said:

Put the pipe dope over the teflon tape.

Click to expand...

Not to get off track, but here’s an interesting fact that causes heated arguments at work.

Multiple guys in my company, who are very good plumbers, apply pipe dope to the threads, then Teflon over it. I have never understood this method. They will tell you “when the Teflon tears it will release into the threads”.

Well....I still do it the “right way”. But in their defence it seems to work for them. One guy has been doing it almost as long as I’ve been alive and rarely a leak.

Thoughts?

Matt30 said:

Not to get off track, but here’s an interesting fact that causes heated arguments at work.

Multiple guys in my company, who are very good plumbers, apply pipe dope to the threads, then Teflon over it. I have never understood this method. They will tell you “when the Teflon tears it will release into the threads”.

Well....I still do it the “right way”. But in their defence it seems to work for them. One guy has been doing it almost as long as I’ve been alive and rarely a leak.

Thoughts?

Click to expand...

The teflon/pipe dope trick seems to work. No leaks and these connections have been troublesome. Must be some merit to it. Wish I would've applied it like this to all the threads. Probably would've helped with my gas line as well lol.