Hot Topics: Fixing a Hydronic Heating System

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Original Post: Hydronic system repair

stolen - Member

I wanted to get everyone's feedback on an upcoming project. I need to reroute a section of baseboard piping to make way for a door, my system doesnt have a pressure reducer, and i've been told my tridicator doesnt work. Figured I'd drain the whole system, make all repairs, then fill the system. Does this checklist seem complete/accurate?

1. Drain system

1.1. Turn off boiler

1.2. Set zone valves to manual

1.3. Drain entire system from boiler drain

2. Modify/repair system

2.1. Install pressure reducer valve

2.2. Replace tridicator, using Teflon tape

2.3. Reroute section of baseboard pipe

3. Fill system

3.1. Close ball valves to zone 1 and 2

3.2. Bleed air/fill zone 1

3.3. Bleed air/fill zone 2

3.4. Open ball valves for zone 1 and 2

3.5. Set zone valves to automatic

3.6. Turn on boiler

Vermont - Member

". . . my system doesnt have a pressure reducer . . ."

So it operates at whatever the water pressure is coming in from the street or from your well?

stolen - Member

Yeah, just a gate valve with street pressure. Never seen anything like it before.

Steamboy - Member

Many years ago, before PRV's became the norm, hot water systems were manually fed by a shut-off valve. You, as the home owner would regularly check the pressure gauge and would add water if necessary. Today, every one wants "totally automatic", and for good reason. This could explain why your system did not have an auto fill PRV. Most PRV's come set at 12 psig. , which should suffice for a 1-2 story house and 15-18 psig. for a 3 story house.

Years ago we used the "rule of thumb" settings of 12, 15, or 20, psig for a 1, 2, or 3 story house. The correct setting would be just enough pressure to allow you to vent the highest piece of radiation, plus another 2-3 lbs. for safety. You did not say how you are re-routing the piping but If you are rerouting the piping under a door way, the correct way to re-pipe is to run under the door and at the same time over the door with vents, so you don't trap air in the new piping.

stolen - Thread Starter

The PRV i got is set to 15 by default, which should be good for my 2 story home. Im going to reroute the pipe down under the floor into the crawl space, under where the door will go, then back up to continue the loop where it left off. Aside from that, does my sequence of steps make sense? Am i leaving anything out, or is there any trick i should be aware of?

Mike Speed 30 - Member

You don't indicate where you are located. If it is subject to freezing, the crawl space may not be good.

Steamboy - Member

If you are going to drop down under the floor, run horizontal, then go back up after the door you will have a problem venting that new piping. You will have to also pipe up, over then down, to allow for venting that new piping. If you don't understand the piping it may be time to call an HVAC company for help in doing it correctly.

spott - Member

As long as that zone is a loop system there will be no problem dropping down and back up as far as air goes. It is no different than feeding 1 room, dropping into the basement to feed the next if you cannot get through the wall. We do it all the time without problems.

When you bleed your system you are going to raise the pressure to about 28psi and that will force all the air out of the zone. It will have no where to go except out of the draw off.

The cold temp in the crawl space may be another issue. You might want to insulate the pipe and check for cold drafts in direct contact with the pipe. That will freeze pipes quicker than just cold temps.

You do not have to or want to add hivents to this job. In my opinion they are of little or no use in a properly installed loop system.

Hope this helps a little.

stolen - Thread Starter

Helps a lot, thanks. yep, I'm going to insulate and encapsulate my crawlspace, but in the meantime, I'm going to insulate it. Quick question, is regular teflon tape ok to use for the tridicator? Didn't know if its rated for that temperature.

spott - Member

Teflon tape is fine. When putting in on wind clockwise, the direction you turn the gauge to install and start winding a thread or 2 back so as you are winding it will not cut the excess off and get clogged anywhere. Also you do not have to put a lot on. Two or three turns is sufficient for a good seal. Why you wind the tape clockwise is so as you are turning in the gauge the tape will not unwind.

It sounds like a small thing but I've seen contractors do it backwards and then say it's no good and go back to dope.

stolen - Thread Starter

All went as planned, except im running into an issue with my Taco zone valves. When i try to push the lever to manual, it only goes half way instead of all the way to open. Any ideas why? Havent found anything on the internet describing this.

PJmax - Group Moderator

They can be tight as they have a strong spring in them.

Are these newly installed valves?

If new.... is there any chance solder dripped/ran into them?

lawrosa - Super Moderator

"If you are going to drop down under the floor, run horizontal, then go back up after the door you will have a problem venting that new piping. You will have to also pipe up, over then down, to allow for venting that new piping."

This make no sense at all... What do you mean? Its a closed loop... Its been done that way for 60 years or more...

stolen - Thread Starter

"They can be tight as they have a strong spring in them.

Are these newly installed valves?

If new.... is there any chance solder dripped/ran into them?"

They are definitely not new, and it doesn't look like anything is obstructing them.

spott - Member

"They are definitely not new, and it doesnt look like anything is obstructing them."

Don't be afraid to use a little force as there is some resistance to these. That's the way they are made. Make sure the head in on correctly.

Turn on your stat and see if that opens it. If it does your fine.

stolen - Thread Starter

"Don't be afraid to use a little force as there is some resistance to these. That's the way they are made. Make sure the head in on correctly.

Turn on your stat and see if that opens it. If it does your fine."

You weren't kidding, those valves were stiff but did push all the way in with some muscle. I'm all set. Thanks everyone for the help/advice, I really appreciate it.