Insulating Pipes on already oversized boiler

holograham

While I dont want to heat my basement and would love a lower heating bill - my boiler is already 45% oversized and I assume the uninsulated pipes are helping keeping it in balance to a degree (pretty large basement mains). Should I worry about unintended consequences here?

SlamDunk

Maybe. You might short cycle.

ChrisJ

Most of what you dump into the basement ends up in the livingspace anyway.

If your heat is fairly balanced and running good I'd probably leave it alone. Especially since warm floors are nice.

That said..........I would recommend insulating anything that's close to romex or even MC wire. Pex as well.
On some of my pex I insulated the pex it self instead of the steam fittings. My mains are insulated but I got lazy with the fittings.

To me close means a few inches and above the steam pipe. If it's below it's not as important as the ones being roasted above it.

holograham

ChrisJ said:

Most of what you dump into the basement ends up in the livingspace anyway.

If your heat is fairly balanced and running good I'd probably leave it alone. Especially since warm floors are nice.

That said..........I would recommend insulating anything that's close to romex or even MC wire. Pex as well.
On some of my pex I insulated the pex it self instead of the steam fittings. My mains are insulated but I got lazy with the fittings.

To me close means a few inches and above the steam pipe. If it's below it's not as important as the ones being roasted above it.

Right - I dont notice our floors being that warm though. And our first floor definitely is the hottest - assuming all that basement heat is rising up.

ethicalpaul

Just as a data point, can you tell us the EDR of your radiation and the Sq Ft of steam rating on your boiler? Do you find that it cycles on pressure very much, or does it only happen after a larger setback? Thanks!

PS: to answer your question, I wouldn't bother insulating unless you want the basement to be cooler. If you're fine with it as-is, it is hard to make the cost be worthwhile.

holograham

SlamDunk said:

Maybe. You might short cycle.

Can you elaborate on this a bit (even just your definition of short cycling).

My working assumption was yes the total cycle time would go down but that was entirely due to not having the heat up all the basement main pipes. That would simply save me money.

holograham

ethicalpaul said:

Just as a data point, can you tell us the EDR of your radiation and the Sq Ft of steam rating on your boiler? Do you find that it cycles on pressure very much, or does it only happen after a larger setback? Thanks!

PS: to answer your question, I wouldn't bother insulating unless you want the basement to be cooler. If you're fine with it as-is, it is hard to make the cost be worthwhile.

1100 EDR, 1608 boiler

On a cold start to go up 2 degrees it takes about 30-35 mins for the first cycle. Then 90 second cycles on pressure for about 20 mins to satisfy the thermostat

ethicalpaul

Since I'm here, I'll answer for @SlamDunk and he can correct me if he wishes

Since your boiler is oversized, you can have a condition where the boiler cycles "on pressure" meaning that the boiler produces more steam than the system can condense which eventually will cause the steam pressure to rise.

If it gets to the "cut-out" point of the pressure control, then the boiler will shut down until the pressure drops to the "cut-in" point, and will repeat that cycle until the thermostat is satisfied and stops calling for heat.

People don't like that and they call it "short cycling" (even though I think that term is not really appropriate for a steam system cycling on pressure). There's really no harm in it and it is better than the alternative of increasing your "cut-out" point higher, but it bothers a lot of people.

A steam boiler that is size-matched to the radiation in the house will very rarely if ever cycle on pressure like that. By insulating your mains, you are reducing the total radiation in your house, and that can exacerbate this issue, but it probably wouldn't be noticeable.

edit: I just saw your response with your cycling information. Yes, if you insulate your mains, you might see a shorter time to that first cycle and a shorter cycle time after that.

holograham

ethicalpaul said:

Since I'm here, I'll answer for @SlamDunk and he can correct me if he wishes

Since your boiler is oversized, you can have a condition where the boiler cycles "on pressure" meaning that the boiler produces more steam than the system can condense which eventually will cause the steam pressure to rise.

If it gets to the "cut-out" point of the pressure control, then the boiler will shut down until the pressure drops to the "cut-in" point, and will repeat that cycle until the thermostat is satisfied and stops calling for heat.

People don't like that and they call it "short cycling" (even though I think that term is not really appropriate for a steam system cycling on pressure). There's really no harm in it and it is better than the alternative of increasing your "cut-out" point higher, but it bothers a lot of people.

A steam boiler that is size-matched to the radiation in the house will very rarely if ever cycle on pressure like that. By insulating your mains, you are reducing the total radiation in your house, and that can exacerbate this issue, but it probably wouldn't be noticeable.

edit: I just saw your response with your cycling information. Yes, if you insulate your mains, you might see a shorter time to that first cycle and a shorter cycle time after that.

Thanks - this is what I am after. I dont really mind the short cycling. House is big enough that its not that noticeable. I am just thinking I'll save that heat up time so steam gets to the radiators even faster.

I already had a 1k gas bill in November and it wasnt even that cold so its serious money per year.

I also do have a little bit of water hammer/gurgling in the beginning of a heating cycle. I had assumed some of this was the steam pushing alot of condensate through the mains as it initially heats up.

ethicalpaul

Where do you hear this gurgling/hammer? The steam doesn't push condensate through the mains in a normal system...what you might have is a "sag" or low spot in your main or supply piping that is holding condensation.

EBEBRATT-Ed

Insulation is expensive but worthwhile. If it was me and you are going to stay in the house it makes sense to insulate the pipes. You can at least get a price for the insulation material and weigh that against the cost of having a warm basement.

As @chrisJ mentioned some of the basement heat migrates upstairs.

I would insulate and then install a time delay relay. This would lengthen the cycles. Ideally you want to get down to 15-20m min burn time

holograham

ethicalpaul said:

Where do you hear this gurgling/hammer? The steam doesn't push condensate through the mains in a normal system...what you might have is a "sag" or low spot in your main or supply piping that is holding condensation.

A little in the basement at the end of my main that I have super vented (its pretty much the same as open pipe venting there). My theory was when I have a cold start - steam is rushing through that main - condensating a ton and then pushing to the end of the main (where there is also a return line).

I get some other gurgling in my second floor but dont think this is going to be related to this.

holograham

EBEBRATT-Ed said:

Insulation is expensive but worthwhile. If it was me and you are going to stay in the house it makes sense to insulate the pipes. You can at least get a price for the insulation material and weigh that against the cost of having a warm basement.

As @chrisJ mentioned some of the basement heat migrates upstairs.

I would insulate and then install a time delay relay. This would lengthen the cycles. Ideally you want to get down to 15-20m min burn time

I think you mentioned this time delay relay in another thread. Definitely going to look into this. Makes sense to me. I need to give the radiators some time to give off their heat and the current pressure cycle is so silly.

dabrakeman

I agree with @Ebebratt that a time delay relay might be your best approach but depending upon what type of thermostat you have you might be able to just limit your on cycle time to 30 minutes during your recovery. My thermostat allows programming steps every 30 minutes so I start with "off" cycle (very low set temperature) 30 minutes before I want to start my recovery, then 30 minutes cycle at target temperature, 30 minutes off, 30 minutes on etc... My system is similarly oversized by %. 30 minutes is about the max burn time I can have without cycling on pressure if the system is already warm. Can get ~40 minutes from a dead cold system. This has worked fine for me using an Ecobee (turn off the learning/anticipator function) so have been doing it for the last 4 years. Just bringing it up as a potential easy and immediate improvement if you have a capable thermostat.

holograham

dabrakeman said:

I agree with @Ebebratt that a time delay relay might be your best approach but depending upon what type of thermostat you have you might be able to just limit your on cycle time to 30 minutes during your recovery. My thermostat allows programming steps every 30 minutes so I start with "off" cycle (very low set temperature) 30 minutes before I want to start my recovery, then 30 minutes cycle at target temperature, 30 minutes off, 30 minutes on etc... My system is similarly oversized by %. 30 minutes is about the max burn time I can have without cycling on pressure if the system is already warm. Can get ~40 minutes from a dead cold system. This has worked fine for me using an Ecobee (turn off the learning/anticipator function) so have been doing it for the last 4 years. Just bringing it up as a potential easy and immediate improvement if you have a capable thermostat.

I have a Nest thermostat (I know they are disliked here - it came with the house). Not sure I can do that with the Nest.

ethicalpaul

holograham said:

A little in the basement at the end of my main that I have super vented (its pretty much the same as open pipe venting there). My theory was when I have a cold start - steam is rushing through that main - condensating a ton and then pushing to the end of the main (where there is also a return line).

I get some other gurgling in my second floor but dont think this is going to be related to this.

Check the pitch of your main...I could see a nearly flat main causing some condensate to build up that would be cooled by the cold pipe then hit by steam as your main heats up and lets steam pass. After a short time all the condensate would be hot enough that it wouldn't collapse the steam anymore. But with a correct pitch on the main I wouldn't think it would happen.

Insulation might not change this much especially with the setback...the mains will still cool down due to that. But it isn't hurting anything either way.

holograham

ethicalpaul said:

holograham said:

A little in the basement at the end of my main that I have super vented (its pretty much the same as open pipe venting there). My theory was when I have a cold start - steam is rushing through that main - condensating a ton and then pushing to the end of the main (where there is also a return line).

I get some other gurgling in my second floor but dont think this is going to be related to this.

Check the pitch of your main...I could see a nearly flat main causing some condensate to build up that would be cooled by the cold pipe then hit by steam as your main heats up and lets steam pass. After a short time all the condensate would be hot enough that it wouldn't collapse the steam anymore. But with a correct pitch on the main I wouldn't think it would happen.

Insulation might not change this much especially with the setback...the mains will still cool down due to that. But it isn't hurting anything either way.

I actually just did check and fix the main pitch. I also had some wonky piping removed (multiple areas where the piping changed diameters - likely left over from old boilers removed and lazy plumber piping with what they had. That has helped eliminate water hammer.

What I think happens now is on a cold start - my mains condensate like crazy - they are pitched correctly
now and the water flows quickly. So I get about a 1minute of gurgling. Its not terrible so I can live with it. I plan to insulate the pipes in Jan which I think will eliminate this.

SlamDunk

We like photos.

What @ethicalpaul said about short cycling is spot on. I dont like it because it wreaks of "it ain't right". Properly sized, the burner turns off on thermostat only.

But, other than that, it's just a bunch of clicks from the boiler's pressuretrol, auto damper(if installed) and gas valve.

ethicalpaul

So I get about a 1minute of gurgling. Its not terrible so I can live with it. I plan to insulate the pipes in Jan which I think will eliminate this.

I'd love to see this--you aren't in NJ by chance?

holograham

ethicalpaul said:

So I get about a 1minute of gurgling. Its not terrible so I can live with it. I plan to insulate the pipes in Jan which I think will eliminate this.

I'd love to see this--you aren't in NJ by chance?

I am - North Jersey

I should mention my boiler is oversized and the header piping is wrong. I dont plan on fixing that near term given the boiler is ~16 years old already. I'm doing all the extraneous things first and

holograham

SlamDunk said:

We like photos.

What @ethicalpaul said about short cycling is spot on. I dont like it because it wreaks of "it ain't right". Properly sized, the burner turns off on thermostat only.

But, other than that, it's just a bunch of clicks from the boiler's pressuretrol, auto damper(if installed) and gas valve.

What pictures do you want? I know I am oversized so I guess some of this is all expected. When I insulate - I will be even more oversized. I still think insulation is the way to go short term. When I replace my boiler I will definitely have it all done correctly.

Jamie Hall

Just remember that insulation is not just for heat loss. It will help speed and thus even out steam distribution in the mains -- and any runouts or risers you can insulate as well.

Big Ed_4

Maybe with a 2.5",3" main . But most residential steam systems were installed with a 2"main , for the ease and price . To handle the condensate in the smaller pipe they were insulated ....

holograham

Jamie Hall said:

Just remember that insulation is not just for heat loss. It will help speed and thus even out steam distribution in the mains -- and any runouts or risers you can insulate as well.

I am insulating everything in the basements - risers in walls so cannot insulate them.

holograham

Big Ed_4 said:

Maybe with a 2.5",3" main . But most residential steam systems were installed with a 2"main , for the ease and price . To handle the condensate in the smaller pipe they were insulated ....

I have 3 inch mains in the basement. Dont know the risers size as they are in the walls.

EBEBRATT-Ed

@holograham

Do you only get the noise on a cold start or does it happen at other times?

holograham

EBEBRATT-Ed said:

@holograham

Do you only get the noise on a cold start or does it happen at other times?

I get lots of different sounds. Nothing individually is super alarming. But I dont have "silent steam heat" for sure.

End of one main has some mild gurgling on a cold start. This was new when I got main venting added (I had no main vents as of 2 weeks ago).

I get a couple moderately loud thunks on cold start that appear to come from the second floor risers.

I have very strange second floor gurgling/rush of water. Kind of like a mix between a toilet flushing and a kettle boiling. This is the loudest and occasional wakes us up. Typically on very cold nights when the heat comes on at like 2am.

I get some occasional radiator dings on startup. Not super loud.

I get occasional radiator dings on cooldown. Not super loud. Assume this (and above) are thermal expansion related.

bburd

There is no good reason to insulate the condensate returns. Just the steam mains, supply risers and runouts.

holograham

bburd said:

There is no good reason to insulate the condensate returns. Just the steam mains, supply risers and runouts.

I thought Dan recommends it.

bburd

holograham said:

There is no good reason to insulate the condensate returns. Just the steam mains, supply risers and runouts.

I thought Dan recommends it.

In my experience there is simply no reasonable payback because so little heat is involved. It is just a trickle of water.  1/1700th the volume of the steam.

holograham

bburd said:

holograham said:

bburd said:

There is no good reason to insulate the condensate returns. Just the steam mains, supply risers and runouts.

I thought Dan recommends it.

In my experience there is simply no reasonable payback because so little heat is involved. It is just a trickle of water.  1/1700th the volume of the steam.

I thought it was also a way to reduce carbonic acid corrosion.

https://forum.heatinghelp.com/discussion/97043/should-steam-return-lines-be-insulated

ethicalpaul

How does water in the wet return absorb anything regardless of temperature?

This stuff is interesting but I don't see how we can control it in our home systems:

In even a slight presence of water, carbonic acid dehydrates to carbon dioxide and water

(from the wiki entry)