Passive ghost flow in fintube during Summer

Kal Row

no to mention the drastic change in comfort testimonial from the old lady that watched tv all night opposite the fintube and then the radiators!!!!

I wish I could take the credit, but it was the homeowner that went to someone else’s house and experienced radiators – and decided to try just the wall opposite his mother in law – and viola – a 40% drop in the gas bill as that zone alone was running the boiler all day!!!

Patchogue Phil_29

Passive ghost flow in fintube during Summer

Just noticed that my hot water baseboard fintube is very warm in my living room. It is the first room on that zone. It is Summer, room thermostat turned down to 55. I am 99% sure the circulator has not run since the fintube gets less warm and becomes room temp the further along the line. The return pipes are room temp except a few feet right near the return inlet on the boiler.

The near boiler piping is such that the supply comes out of the boiler top vertical a few feet, turns horizontal 18 inches to the airscoop and manifold, then turns downward 5 feet before running horizontal for 21 feet (mostly insulated) before it gets to the living room. About 12 feet from the boiler, the ¾ cu pipe is too hot to touch more than 3 seconds.

Am I wrong to figure this is passive heat flow (conduction)? How do I stop the heat flow?

My boiler makes my domestic hot water so it needs to be running in Summer.

Techman

Ghost Flow

Hi Phil! Do you have the flow check open? Do you have two flow checks? One in the supply and one in the return.Does your last name begin with letter Gebbia?

Patchogue Phil_29

Nope.

Not Gebbia.

There is a swing check on the outgoing supply for each zone. No other flow check. I *thought* that the big up-n-down loop off the supply would stop any passive heat flow.

Can I just close the gate valves on the supply (until heating season of course) ? I'd leave the return valves open for thermnal expansion of the water (yes there is an extrolexpansion tank).

ALH_4

Check Valve

I assume this is the first year this has happened and that this is not the first summer for the system? If so, there could possibly be something stuck in the check valve preventing it from seating or the check valve could have otherwise failed. Have you cycled the heating pump on and off to try to dislodge anything that might be stuck in the valve? If this does not work, the check valve may need replacing.

You could shut off the valve to the zone in question to prevent this, but that zone might start to overheat this winter when the water heater calls for heat.

Techman

Phil

Sure,you can shut the valve until the heating season,but here in Medford,it's hot one day then cold the next,even in Dec,Jan ,and Feb.

Patchogue Phil_29

Not new system

I've never noticed this before and the boiler is from 1994.

Frankly I never checked before and just happen to touch the baseboad while plugging someting into the electric outlet just above it. The baseboard is very warm but touchable, not "HOT" like during heating system. It's only slightly warm 15 feet further down the line. After that it is room temp.

No wonder it is warmer in that room during summer and the A/C runs more in that room.

Patchogue Phil_29

Did you mis-speak/type?

You said
"You could shut off the valve to the zone in question to prevent this, but that zone might start to overheat this winter when the water heater calls for heat."

When the water heater calls for heat?

Anyways, I'd only close off the heating zone valve during the Summer when I do NOT need heat.


BUT..... is it that there is *some* flow of hotwater? Or is the heat being conducted thru the pipes/water and to the fintube? I'm thinking it is water flow, and that conduction couldn't get enough heat through the pipes to be noticed.

ALH_4

zones

What I typed wasn't very clear. ;-)

I just mean that if there is flow through the heating zone when the dhw pump is running it may get worse to the point where you are overheating the zone, and if the zone was shut off you wouldn't notice it until you opened the valve in the winter and the dhw pump circulates both the coil in the water heater and the water in that zone. I guess what I should have said is that shutting the zone down now just delays having to deal with the problem until winter when you need the heat.

This is one reason why I prefer zone valves to zone pumps. You have positive shutoff on the zones with zone valves.

Patchogue Phil_29

OK, I get what you meant

I'll be replacing the whole system before heating system begins so I won't have that issue anymore.

Kal Row

before you spend a lot of money on this..

why dont you simple close the valves - there has to be valves by the pumps and zones etc, just shut them for the summer - for the winter, a little in-pipe convection usually helps even out the house temps

and if you dont have them, you need to put them in anyway for service first,

and if your baseboard system is a one zone monster - then you should redo anyway

Kal Row

however...If you want to “invest” in an upgrade…

I would give you a performance based contract to replace your baseboards with cast iron rads

I will get my subs to come out to you and replace them at parts and labor cost only

my profit would be half the cost of therms per degree day saved for 10yrs

ie if you used 4 therms on a 24hr period of 40f outside temps now and after the change you only use 2 therms, then you own me the cost of 1 therm which is half the therms saved

of course, you would have to be crazy to take this deal, as any contractor wont charge you that much profit, and then you can keep all that mullah-schmula for yourself – and trust me it’s serious money – probably pay for the change out in 1 or 2 seasons

notice I am not talking about changing boiler, controls, zones, outdoor reset, insulation, and all that good stuff, just, changing the fin tube baseboards for flat faced sunrad type cast iron RAY-DEE-8-TORS under the windows!!!

Trust me there is some hard experience behind these bold statements - people don’t believe it, but the difference is day and night, in running costs, comfort, and quietness

This will buy you more than anything else, EN-EEEE-TING!!!

For the next big running cost break – you would need to invest a lot more – like for a modcon boiler with and indirect domestic hot water tank


the attached pics are of the same rad dif angle - job by moses fichman of ENY mechanical

ALH_4

replacement

Sounds like closing the valve is the way to go. You wont hurt anything as long as that thermostat does not call for heat and dead-head the pump for days or weeks.

Are you replacing the entire system? I am not a big fan of baseboard, but it can be used with condensing boilers depending on the amount of baseboard you have relative to the heat load and the piping arrangement.

Sounds like Kal is partial to cast iron radiators. My personal preference is steel panel radiators with TRV's connected to a constant circulation mod/con boiler. I am not sure of the exact cost of cast iron radiators. I would wager the cost is far less for steel than for cast iron radiators, and the performance is nearly identical if not a little better for the steel radiators.

Patchogue Phil_29

replacement

Yes a complete replacement of the heating system EXCEPT for the fintube baseboard.

A lot the fintube it is very new. There is too much of it per room since I've renovated (windows, insulation, air sealing). Heat Loss shows I can run much lower temps, so a new system will have some temp mixing controls.

I did shut off the supply side isolation valves. No heat above room temp is felt in the fintube today.

I still find it odd that there was apparently some hot water flow. No pumps *should* be turning during no heat calls. I would have blamed it on conduction thru the cu and H2O only. I figured the up and down loop on the supply side would block any heat "rising" thru the pipes since the boiler and the zone of fintube are on the same level.

kal_2

only wish you could witness the difference firsthand...

you would chuck brand new fin-tube in a minute – people just don’t believe the 30-50% saving number I throw at them – don’t feel bad you are not the first one ;(

try this - blow across the top of your hand – feels cool – doesn’t it – even though, the air your exhaling is about 90f - now have some else hold their palm 1 inch off your forehead, and feel the infra-red light even though their skin temp is only 85 – the message is clear and simple – heating air to heat people is just plain dumb!!! – air is one of the worst heat transfer fluids – if it was any good – the sun would heat the air and kill us in January, - and yet the sun manages to get 450 watts per square ft (900 summer) on the ground in the winter across 93 million cold black vacuum miles of space – the only kind of complaint I ever got on a radiant job I did was, “too hot” !!! – it’s mostly because people have to learn to set the tstat for 68 and wait for the slab to come to temp – and then just leave it alone – at least with rads the wait is shorter and a tstat per room or rad makes sense


as for being partial to cast - it's not cast that i am partial to, but rather more mass

the more mass and the more visual infra-red surface the better

Patchogue Phil_29

Science

blow across the top of your hand – feels cool – doesn’t it – even though, the air your exhaling is about 90f - now have some else hold their palm 1 inch off your forehead, and feel the infra-red light even though their skin temp is only 85 – the message is clear and simple – heating air to heat people is just plain dumb!!! air is one of the worst heat transfer fluids – if it was any good – the sun would heat the air and kill us in January,


Kal, there's just a bit more physics involved there to keep us from being incinerated from the Sun. And there's a little known secret about evaporative cooling of moving air (wind or bad breath), even if that air is warm. :-)

All kidding aside, YES... radiant heat is wonderful. I'd rather it in the floor than against the wall base. My home decor is not of the Spartan period, we have furniture and want the freedom to place it anywhere along the wall.

Thanks for your input, but I'm not interested in anymore about changing my fintube baseboard to radiant panels right now.

zeke

From your description, it looks like an opening in the check
valve is the only possibility, since the natural convection process cannot occur if the baseboard is on the same level as the boiler.

Also, I do not believe that radiators will make a significant improvement in efficiency. I would grant that the increased heat capacity would even the temperature and reduce the cycling frequency somewhat, but not enough to make a big capital investment.

Now Kal's deal about taking half of you future savings would amount to you getting NO benefit from his socalled improvemnt, since the present value of all your future savings for 10 years would be about 1/2.
So, don't take the deal.

Patchogue Phil_29

No deal

Trust me, I wasn't even remotely interested in Kal's deal! LOL

I'll run lower temps thru the overkill baseboard fintube. It was probably working hard at 180* when I had leaky old windows, barely any insulation and no airsealing at all.

Doc Radiant

Phil, I have never been a fan of using swing checks for this purpose. When you re-pipe the system, use a good old iron-body flow control valve.

BTW, I live in Patchogue too!

Patchogue Phil_29

Hey Neighbor

small world!

Are you in the heating biz?

Doc Radiant

I was for over 15 full-time years. Then spent a year with RTI, nearly 4 with Embassy and then 7 with Slant/Fin, all related to radiant heating sales & training. I've been working from home since late last year doing some Internet stuff (need to get a "real" job again before wife kills me).