Water Temp. Problem

Frank_3

Jamie,

Let's ignore the radiant for a minute, since that part is working. Here's what I've got so far ...

a) The house is quiet, no zones are calling for heat, not a creature is stirring, and the boiler just finished a cycle so the P&T gauge shows 180 degrees. Those are the starting conditions, ok?

b) Now, the house zone calls for heat. The 007 house circulator kicks on. The 0010 primary loop circulator kicks on. The boiler P&T gauge starts showing a temperature drop and at 160 the boiler fires and keeps firing.

c) The P&T drops to 130 and all that time the 007, 0010 and boiler are working like mad. Yes? When the house zone satisfies the 007 goes off, the 0010 goes off, and the boiler keeps going until the P&T shows 180.

Is that what's happening? If not then which part is wrong?

Jamie_6

We can not maintain temp.

Guys, here is one for ya!

We are not able to maintain temp. on our primary loop when ever the house circ. comes on. As soon as the house circ. goes off the boiler goes right back up to 180 and the radiant starts to satisfy again.

I'm really worried because this boiler is seeing some cold temps. coming back.

Any ideas what could be going on?

Thanks,

Jamie

Jamie_6

HELP!!!!!!!!!!!!!!!

ta finnegan

Questions

What is the aquastat set at now?

Is the size of the boiler adequate for the max load?

Do you have good air separation devices in the system?

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Dana

Put the pipe sizes and BTU loads on your drawing. Boiler should be pipied primary/Secondary and its not. What kind of boiler is it, model, manufacturer. Heat zone lengths, etc. 11/4" mains at 180,000 btus is borderline. Why is the

Frank_3

I'll second that ...

...about the aquastat. I'm confused about the temperatures you're showing in the drawing. If the boiler is piped as part of your primary loop, and all the water passes through the boiler, then how can the primary loop temperature only be 130 degrees if the boiler is showing 180 when the house circulator goes off?

Is the drawing correct?

The other thing that comes to mind is that the only way the 007 house circulator can overpower the 0010 (which is what would be happening according to your description) is if either there's something blocking the primary loop and making the flow rate very low, or the 0010 may be faulty and not pumping at capacity.

SO, check the 0010 for worn or broken impellers and/or remove the 0010 and run a snake through the primary loop and see if something has it clogged up somewhere.

Oh, the assumption I'm making is that the 0010 is either on constant circulation or always comes on when any of the zone circulators goes on. If that's not the case then there's your first thing to fix.

Frank_3

I'll second that ...

...about the aquastat. I'm confused about the temperatures you're showing in the drawing. If the boiler is piped as part of your primary loop, and all the water passes through the boiler, then how can the primary loop temperature only be 130 degrees if the boiler is showing 180 when the house circulator goes off?

Is the drawing correct?

The other thing that comes to mind is that the only way the 007 house circulator can overpower the 0010 (which is what would be happening according to your description) is if either there's something blocking the primary loop and making the flow rate very low, or the 0010 may be faulty and not pumping at capacity.

SO, check the 0010 for worn or broken impellers and/or remove the 0010 and run a snake through the primary loop and see if something has it clogged up somewhere.

Oh, the assumption I'm making is that the 0010 is either on constant circulation or always comes on when any of the zone circulators goes on. If that's not the case then there's your first thing to fix.

And double check that drawing. Did you leave stuff out?

Jamie Pompetti

Frank, Thanks for the response! What I'm trying to say is that when the main house is drawing water the boiler temp does drop to about 130 degrees. When the house finally satisfies and the radiant is still calling the boiler temp will climb back up to 180 with no problem. I have been piping just about all my systems this way and was not aware that it was wrong. (will you show me how I should be doing it)I used to connect the main primary and have a supply & return tee to the boiler, but that ment another pump. What I think may be happening is the existing house has 2 1/2" mains and flow is to easy. I was thinking of adding some kind of flow restriction.

Jamie Pompetti

Frank,

Thanks for replying to my post! What I was trying to say is that whenever the house calls the primary loop drops to about 130 degrees on the supply and 110 on the return. Once the house satisfies (and if the radiant is calling) the boiler will hit 180 and run off of its aquastat till it satisfies then turn off. From what I understand you said I piped the system wrong? I was curious on how I should pipe it? What I think is happening is that the main house must have really easy flow through the big 2" black mains. I was thinking of throttling down the ball valve on the secondary loop of the main house, maybe that would restrict some flow?

Thanks for the input,
Jamie

Steve Eayrs

What is the house

load? BTUs? Are they high temp heat zones? When you first turn on the house supply pump, what is the S & R temps on the house piping?
Are the pumps you have on your radiant zone drawings, injection pumps? If not, how are you mixing down the radiant temps?

Steve

ScottMP

Jamie

From what I am reading is that the syetms works fine untill the house zone with the 2" black steel piping comes on. Is that correct ?

You are feeding the radiant floor with injection, correct ?

Whats the load on the house zone ?

What are the return temps cpming back from the house zone.

It sounds as if the house zone is sucking the BTU's right out of it. Maybe too much on that one zone. I hope the boiler is sized large enough for the total load, ( existing and what you put in , better check the loads ).

As allways, nice neat work from you Jamie.

Let us know what you find.

Scott

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Jamie Pompetti

You are always to kind Scott! Thanks for the comments and the reply! The system is a cold start system so lets say the radiant injection comes on. The boiler will cycle of the limit and work fine, but (Behold the Ultimate Truth) once that main circ. comes on all the temp is gone and I am getting a 20 degree drop between the supply and return of the house?

The radiant is a WIRSBO 212 injection system.
The total load on the house (including the radiant)@ 5 degrees outside is 168,000 and I have 180,000.

What to do? I should have checked the drop across the boiler prior to the radiant instal!

Jamie

ScottMP

What happens

If you run just the house zone, and shut off the floors, does it keep up ?

If you have a twenty degree drop but the loop is down around 130, whats temps going out to the house ? 130 ?
Is the return then 110 ?

With near boiler piping and maybe a gas problem, you might not be getting 180,000 out of the boiler.

How far a run is the old existing zone ? And whats on it ?
Cast iron rads or copper finned tube ?

By the way, whats the temp at your place this week ? Under 5 degrees ?

Scott

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Frank_3

Still confused.

Jamie,

Let's ignore the radiant for a minute, since that part is working. Here's what I've got so far ...

a) The house is quiet, no zones are calling for heat, not a creature is stirring, and the boiler just finished a cycle so the P&T gauge shows 180 degrees. Those are the starting conditions, ok?

b) Now, the house zone calls for heat. The 007 house circulator kicks on. The 0010 primary loop circulator kicks on. The boiler P&T gauge starts showing a temperature drop and at 160 the boiler fires and keeps firing.

c) The P&T drops to 130 and all that time the 007, 0010 and boiler are working like mad. Yes? When the house zone satisfies the 007 goes off, the 0010 goes off, and the boiler keeps going until the P&T shows 180.

Is that what's happening? If not then which part is wrong?

Are you measuring the 130/110 temperatures at the supply & return for the house zone (where the two ball valves are, in the photo) or are you measuring that at the supply/return of the boiler going to the primary loop? If you're measuring at the house zone, then what temperatures do you get at the boiler supply and return? (Boiler supply should match P&T gauge, naturally.)

Frank_3

Still confused.

Jamie,

Let's ignore the radiant for a minute, since that part is working. Here's what I've got so far ...

a) Turn off the radiant, let the house cool down for a few hours. The house is quiet, no zones are calling for heat, not a creature is stirring, and the boiler just finished a cycle so the P&T gauge shows 180 degrees. Those are the starting conditions, ok?

b) Now, turn up the house thermostat so that the house zone calls for heat. The 007 house circulator kicks on. The 0010 primary loop circulator kicks on. The boiler P&T gauge starts showing a temperature drop and at 160 the boiler fires and keeps firing.

c) The P&T drops to 130 and all that time you've confirmed that the 007, 0010, and boiler are working like mad. Yes? When the house zone satisfies the 007 goes off, the 0010 goes off, and the boiler keeps going until the P&T shows 180.

Is that what's happening? If not then which part is wrong?

Are you measuring the 130/110 temperatures at the supply & return for the house zone (where the two ball valves are, in the photo) or are you measuring that at the supply/return of the boiler going to the primary loop? If you're measuring at the house zone, then what temperatures do you get at the boiler supply and return? (Boiler supply should match P&T gauge, naturally.)

Frank_3

Still confused.

Jamie,

Let's ignore the radiant for a minute, since that part is working. Here's what I've got so far ...

a) Turn off the radiant and main thermostats and let the house cool down for a few hours. The house is quiet, no zones are calling for heat, not a creature is stirring, and the boiler just finished a cycle so the P&T gauge shows 180 degrees. Those are the starting conditions, ok?

b) Now, turn up the house thermostat so that the house zone calls for heat. The 007 house circulator kicks on. The 0010 primary loop circulator kicks on. The boiler P&T gauge starts showing a temperature drop and at 160 the boiler fires and keeps firing.

c) The P&T drops to 130 and all that time you've confirmed that the 007, 0010, and boiler are working like mad. Yes? When the house zone satisfies the 007 goes off, the 0010 goes off, and the boiler keeps going until the P&T shows 180.

Is that what's happening? If not then which part is wrong?

Are you measuring the 130/110 temperatures at the supply & return for the house zone (where the two ball valves are, in the photo) or are you measuring that at the supply/return of the boiler going to the primary loop? If you're measuring at the house zone, then what temperatures do you get at the boiler supply and return? (Boiler supply should match P&T gauge, naturally.)

Jamie Pompetti

Scott,

If I run just the house it makes temp on the t-stat but we get some cold temps back to that boiler (about 110). The house has huge convectors and some radiators all over the place. Some as big as my desk.

I also thought about the amount of btu's I am geting but I have not clocked the meter yet! I think I am going to have to do that next. Also, the outside temp has been around 10 (I do think we are pressing the envolope with that)

I stopped by this morning and throttled back the ball valve on the return side so the system and managed to get the boiler to run off of the aquastat. When I stopped back around four everything was satisfied. Lets see what happens tonight?

Jamie

kevin

i think..

your primary loop is undersized..max on 1.25" is usually 140,000 btu i would have kicked up to 1.5"copper. Is it possible to put some type of reverse acting aqua stat to stop the house zone from calling untill the boiler comes up to temp.? Just a thought...kpc

John Cockerill

Why Cold Start

With a tiny boiler you need readiness for call from all these supply loops. Insulate first stage supply loops and assuming all above is in order, regulate your aquastat for balance. Switch to maintenance of temp mode at limit in first stage. Monitor circulation times at different temps. adjust aquastat and observe behavior of first stage return temperatures under load. wwwexqheat.com

John Cockerill

Why Cold start

See note above. There must be a ready supply of water in the first stage to get btu's up to calling zones. The first stage circultor should be running continuously as mentioned above. Check the differential HL-LL ( 15 degrees ). Adjust to taste.

Going back to your original drawing the supply pipes should be comming off the top pipe and your returns in the bottom. This way you would have a good even supply to all zones with the cold water comming back to the later stage of the first stage. As you have it the cold water from the first loop is feeding into the supply of the second and so on till there is nothing left for the last loop. ie 100 degrees. www.exqheat.com

John Cockerill

expansion tank

Your drawing looks like expansion tank is on the cold water side???

ScottMP

Jamie

Is the boiler original ?

If it is, it probable did O.K. by itself, really low returns but eventually heated the home. The radiant just threw a wrench into the works and put it over the line during extreme weather.

It sounds like that house loop just SUCKS the heat right out of the loop. I was thinking a different pump but if the BTU's are'nt there, than you can't pump them. Maybe a buffer tank to give some volume to the system ?

I think maybe a new boiler. Or a smaller one just for the radiant.

Just thinking out loud.

Scott

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Terry

my thoughts

Here is my prospective...

Load is 168,000 btu/hr @ Design Temps.
Boiler is 180,000 - BUT .. is the 180,000 the input or output? (Usually a nice round number like 180,000 indicates INPUT). a 180 input boiler will put out aprox 136,000 btu (depending on ; Efficiency, Altitude & Fuel type)

1-1/4" Mains OK for 136mbh OUTPUT. BUt 1-1/2" better for 168,000 Net Load. NOTE: this size diff will have velocity/pressure drop probs. But if you are seeing 20 deg delta-T's - then we are delivering btu's. (But do we have enuff?)

Try isolating Radiant zones & run only house.. if possible, isolate sections on the house zone & run system to see if primary loop maintains high temp. IF it does, slowly open isolated zones & monitor primary temps & delta-t's - This should help indicate if the boiler/primary loop are sized adequately. (Analagy: Depositing $1320 per month into a bank to cover $1600 monthly alamony payments)

Good Luck!
Terry T

hot_rod

No boiler protection?

Here is another way to pipe that so you can protect the boiler. Sounds like you have a pretty high mass distribution that is pulling you boiler down. Similar to the problem hb discovered on a slab radiant.

The primary loop pipe is sized based on delta t, nothing else. 1-1/4 would be fine, consider a 30 or 40 degree delta t, when you sort this out.

if you know flow rate, and can measure the delta t, you can calculate exactly how much heat you are actually producing.

Clock the gas meter to be sure of the output. Did you run a combustion analyzes to see how the boiler is firing? Could it in fact have the wrong orfices?

The load calcs could be off??

hot rod