Heating Help

Securing PVC fitting cover inserts

@ February 20, 2012 11:45 AM in Securing PVC fitting cover inserts

Thanks for your reply, Paul.  I understand using the tacks and tape to secure the fitting covers themselves; are you saying you also use the tape to help secure the fiberglass inserts to the pipe (when necessary) before putting the covers on?

Securing PVC fitting cover inserts

@ February 20, 2012 11:06 AM in Securing PVC fitting cover inserts

I watched that video (and the other 3 in the same series) before I started this project a few months ago.  I just re-watched the particular one you referenced.  At 7:24 I see the person wrapping the insulation blanket with what looks like tape, prior to putting the fitting cover over it -- but I'm not sure what kind of tape it is.  Do you think it's PVC/vinyl/Z-tape ?  Is that what you're recommending?  Thanks.

Securing PVC fitting cover inserts

@ February 20, 2012 9:08 AM in Securing PVC fitting cover inserts

I'm insulating my home hot water (not steam) heating black pipes in my unfinished basement.  When I put a PVC fitting cover over an elbow or a T or any other fitting, I first position, tuck and fold the fiberglass insulation insert around the elbow/T/etc. prior to putting the cover on.  Once on, I secure the cover with Z-tape.  The problem is that sometimes part of the insert starts coming away from the pipe before I put the cover on.  Even if I do get the cover on before the insert starts coming off, I'm concerned that it's not secured well enough under there.  What do people here recommend to secure the insert onto the pipe before putting the cover on?  I didn't think that using plastic cable ties would be a good idea due to the heat.  I was thinking a single wrap of some sort of thin bare wire, but what?  Stainless steel?  Galvanized?  Or is there something better?  Thanks.

Our system doesn't actually have a leak

@ February 14, 2012 6:38 PM in Where does the water go?

(as far as I know).  It was just a question to understand why there's an automatic water feed if a system is running normally (not leaking).  It sounds like it's more of a safety thing, i.e. if there WAS a leak, it would feed more water to make it up.

Where does the water go?

@ February 14, 2012 5:22 PM in Where does the water go?

Here's a question from a newbie to HVAC (me).

My house was built in 1931 (if that matters).  I have a gas-fired hot water (not steam) heating system.  The boiler is a Weil-McLain series 8 CGM-5, with black pipes leading to the radiators upstairs.  I know there's a water supply to the boiler (the line with a pressure reducer and backflow preventer).  But other than someone manually draining water from the system for whatever reason, why does the system need a continuing source of water?  I thought the "system" was sealed, so if water is lost, where is it going?  Thanks.

ASJ safety question

@ January 29, 2012 11:27 AM in ASJ safety question

I am in the process of insulating my hot water (not steam) heating pipes in my unfinished basement.  These are black pipes feeding radiators on the upper floors.  I am using 1"-thick wall fiberglass tubes, with ASJ facing.  I'm about to insulate a section of 1" IPS pipe, specifically supply pipe.  My system is set at a high limit of 150 degrees.  The return pipe is running in parallel just about exactly 1" away from the supply pipe, so in this case I will probably not be insulating the return pipe there since there isn't sufficient clearance.  The issue is that the pipe insulation on the supply pipe will just butt up against the return pipe.  Specifically, the ASJ will butt up against it.  I've read that the ASJ itself is rated up to 150 degrees F.  Since my system is set to a high limit of 150 degrees, the return pipe should be less than 150 degrees (and when I've measured it, it is, but of course it's not very far from 150).  I've also read that the auto-ignition temp of paper (in general) is around 450 degrees (not sure if that's F or C).  Either way, I'm trying to make sure that having the ASJ butting up against the return pipe is safe.  Alternatively, I could do a relief cut in that area so that the ASJ does not touch the pipe, or I could cut away a long section of ASJ entirely, but I'd rather not do that unless I have to.  Thanks for any advice.

I should have mentioned ...

@ January 21, 2012 10:46 AM in What should boiler high limit be?

that I have old (1931-era) cast-iron radiators.

What should boiler high limit be?

@ January 21, 2012 10:18 AM in What should boiler high limit be?

I have a Weil-McLain series 8 CGM-5 hot water heating boiler.  Runs fine.  (We have a separate DHW heater.)

About two years ago the 30 PSI PRV started spurting out small amounts of water, infrequently.  When I checked, the pressure was at 25, when it's normally around 18.  I had a pro come out to check it.  He checked the PRV (thought there might have been some grit partially blocking it), and drained the overhead expansion tank since it hadn't been done in 3 years.  He also turned the high-limit down from 150 to 140, saying "the radiators are as hot as they need to be."

About 1.5 months ago I noticed that, although the booster pump would remain on and continue circulating water, the gas to the boiler would constantly turn on and off, since it was hitting the 140 high-limit.  I turned the high-limit back up to 150, and have had no problems with the PRV or pressure (reaches about 18), and it's not cycling the gas nearly as often.

However, it still continues to cycle the gas on and off some, 2-4 times each heating cycle (again, with the booster remaining on).  I am wondering whether the high-limit should be turned up to, say, 160.  I mention 160 because I have a note from some service person many years ago which says that the max should not be more than 160; I don't know why.

This boiler has only a high-limit adjuster.  No low-limit or differential adjusters.

Should I turn it up to 155 or 160 to reduce the gas cycling?  On the other hand, will I end up using more gas that way, since it takes ever more energy to heat water higher and keep it that high?  Thanks.

Insulate over a pipe union, or not?

@ January 17, 2012 11:03 AM in Insulate over a pipe union, or not?

Hmmm, I just noticed the title of your comment:  "Full thickness insulation."  I think that answers my question in the affirmative.

Insulate over a pipe union, or not?

@ January 17, 2012 11:01 AM in Insulate over a pipe union, or not?

Thanks for your response, Jason.  I'd like to under stand why, since my pipe insulation is thick enough to allow for a relief cut in order to fit around the union, you are suggesting instead covering the union (and smaller pipe insulation) with larger insulation?  Is it because doing a relief cut reduces the amount of thermal insulation, and the larger insulation (not needing a relief cut) is full thickness?  Thanks.

Insulate over a pipe union, or not?

@ January 16, 2012 2:50 PM in Insulate over a pipe union, or not?

Thanks for your response, Steve.  Since I'm  using 1"-thick tubes, I have enough room to do a relief cut with the correct size tube.  If I hang a tag marked UNION, why also cover it with a piece of larger pipe size insulation?

Insulate over a pipe union, or not?

@ January 16, 2012 1:20 PM in Insulate over a pipe union, or not?

I'm in the process of insulating my hot water (not steam) heating pipes in my unfinished basement.  I'm using 1"-thick-wall fiberglass tubes.  I've now come to my first union, and I need to know whether I should insulate over it (using a relief cut so it fits), or leave a gap for it so it remains uninsulated.  The reason I ask is that while researching pipe insulation installation, I found a video produced by the NIAC Association, which says "Unions on hotlines are usually left bare so they can be found and pipe wrenches used to disconnect them."  You can see the video at http://www.youtube.com/watch?v=fdw-NjfVDDk ; the relevant portion begins at 5:11.  Note that it says usually.  What do people here think?  Insulate over it, or leave a gap for it?  Thanks.

Priority when insulating hot water heating system pipes

@ January 16, 2012 9:39 AM in Priority when insulating hot water heating system pipes

Assuming I understand what you mean by emitters, we have radiators.  There wasn't a problem, per se, but the black pipe in the basement is giving off a lot of heat, which is making our unfinished basement much warmer than necessary, and we'd rather preserve that heat for the living space upstairs.  We have no intention of ever finishing the basement.  I understand that making the basement cooler may remove some heat rising up to and heating the first floor, but a lot of the heat being given off by those pipes is being wasted heating the basement walls, floor, contents, etc.

I am going to go with what Steve (and others) recommended, namely finishing all the supply lines first.  Thanks for your help, everyone.

Priority when insulating hot water heating system pipes

@ January 15, 2012 5:31 PM in Priority when insulating hot water heating system pipes

Oops, I meant it would be easier for me to move on to the main RETURN pipes since
there are fewer of them and straighter runs, but I want to do this job right.

Priority when insulating hot water heating system pipes

@ January 15, 2012 5:28 PM in Priority when insulating hot water heating system pipes

Harvey:  I checked out the web site you suggested (www.engineeringtoolbox.com).  The table and graph there are for copper pipe, and I have black pipe (which I assume is cast iron).  Perhaps the info for copper is similar for black pipe.  It seems clear that there is more heat loss with larger diameter pipe than smaller, which makes sense and is what I assumed.  But I'm not sure how that helps me answer my question, namely which to do first, the rest of the (smaller diameter) supply pipes, or the (main) return pipes.  Larger pipe may lose more heat for a given length, but I want to know if it's more important to finish supply pipe first before moving on to return (STEVEusaPA seems to think so).  It would be easier for me to move on to the main supply pipes since there are fewer of them and straighter runs, but I want to do this job right.

I'd appreciate hearing what others think, too.  I'm hoping to get a consensus.  Thanks.

Priority when insulating hot water heating system pipes

@ January 15, 2012 3:49 PM in Priority when insulating hot water heating system pipes

I have a natural-gas hot water (not steam) boiler heating system.  (Domestic hot water provided separately by a water heater.)  The black pipes from the boiler run near the ceiling of my unfinished, air-sealed basement.  Two walls are completely underground, two are partially so.  It's warmer in there than it needs to be.  I'm in the middle of insulating the pipes, using 1"-thick-wall fiberglass.  I've just finished insulating the main (trunk) supply lines.  The question is, what should the priority be of what to do next?  Should I do the main return lines next?  Or continue with the supply lines, i.e. branches, and even twigs, before moving on to the return lines?  I had been thinking I'd get the biggest bang for the buck doing all main lines first (supply and return), before doing the many smaller diameter pipes, but wanted to get peoples opinions.  Also, I was thinking that by leaving the branch and twig lines uninsulated, that would ensure that the basement doesn't get too cold; I was thinking that after finishing the main lines if it's still warm enough down there to safely insulate more, I could always do the branches/twigs then.  Thanks.