One zone calls for heat whole house gets hot

[VtRv]

I have a Tarm Solo Plus that I've had for a few years now. I have 500 gallons of pressurized storage and my house has circulator pumps for each zone. I have 5 zones one of which is my hot water tank. My problem is that when one zone kicks on all the zones get hot.

I'm sure this isn't enough info to be useful. I have a circulator on the back of the tarm to circulate water from the Tarm to the storage tank. Then there is a circulator with zone valve between the tank and the rest of the house heating system which as I said is set up so each zone has a circulator.

Any suggestions. My house gets to be 80 degrees because one zone is calling for heat.

 

[hondaracer2oo4]

Can you draw a simple diagram of what you have for us? This must be a new problem? Did you change anything?

 

[VtRv]

I'm basically using this design but with circulator pumps vs zone valves. Sorry I don't know how to draw a system my self. I haven't changed anything and this has been an ongoing issue since I've installed it. Just seems to be getting worse.

 

[hondaracer2oo4]

We need to know how your exact system is piped to be able to tell you where the problem is. Can you just draw on a piece of paper how yours is plumbed, take a picture of it and upload it?

 

[maple1]

Sounds like you should maybe swap out your zone circs for zone valves - otherwise that first pump will move water though the individual pumps whenever it is running.

But what you described isn't quite what the diagram shows - so not sure exactly what you've got. Does that first pump get called on any heat demand?

 

[velvetfoot]

With those 5 circulators, do you really need another pump on the tank. I wonder if it would work better if you disconnected the tank pump temporarily as a test, and maybe took it out later if it worked.

Now, you may still have an issue when the wood or oil boiler is on and their pumps are running. I got some flow in my zones when their zone circs weren't running under those conditions, so I wound up replacing the zones' flow check valves with zone valves. Redundant, yes, but it was a backfit system, like many.

 

[Mike Fromme]

Flow checks.

 

[maple1]

With those 5 circulators, do you really need another pump on the tank. I wonder if it would work better if you disconnected the tank pump temporarily as a test, and maybe took it out later if it worked.

That might work too, but would still maybe produce some roundabout zone flow if the zone circs don't have check valves in them?

 

[velvetfoot]

That might work too, but would still maybe produce some roundabout zone flow if the zone circs don't have check valves in them?

I just meant temporarily, and just for the tank. Each zone would take what it needs from the tank. The second paragraph in my response would maybe address when a boiler pump is running. For me, the flow check valves didn't stop the boiler pump's flow, especially if it was turned up some. For me, it wasn't a bunch, because the pump wasn't turned up that much.

 

[Bob Rohr]

In that drawing the pumps are all in series. When you series pumps you double the head. Most zone valves have about a 20 psi shut off pressure. No that is the delta P that the pumps develop, not the static (gauge) pressure that you read.

I suspect any loop that has zone valves is bleeding by the ZVs.

 

[velvetfoot]

suspect any loop that has zone valves is bleeding by the ZVs.

My Taco Zone Sentry valves are ball valves. The brochure says 300 psi max.

With that "Load Circ", as seen in the diagram, along with a boiler feed pump, that's a lot.

 

[leon]

I have a Tarm Solo Plus that I've had for a few years now. I have 500 gallons of pressurized storage and my house has circulator pumps for each zone. I have 5 zones one of which is my hot water tank. My problem is that when one zone kicks on all the zones get hot.

I'm sure this isn't enough info to be useful. I have a circulator on the back of the tarm to circulate water from the Tarm to the storage tank. Then there is a circulator with zone valve between the tank and the rest of the house heating system which as I said is set up so each zone has a circulator.

Any suggestions. My house gets to be 80 degrees because one zone is calling for heat.

====================================================================================================


You have a bit of a mess there.

You have two expansion tanks when you should have only "one" for the entire system.

If the system is plumbed as the diagram shows your circulators have no point of pressure change in the way is plumbed.

That is part of your plumbing problem.

The other issues include that the boilers should be plumbed in series not parallel UNLESS there is a temperature balancing circulator between the two boilers.

It all depends on whether you want to lower the triple aquastat settings for the system to ride out the winter and then fix the mess in the off
season or fix it now as you need a to have a B+G or TACO representative look at your octopus of a system.

 

[velvetfoot]

====================================================================================================


You have a bit of a mess there.

You have two expansion tanks when you should have only "one" for the entire system.

If the system is plumbed as the diagram shows your circulators have no point of pressure change in the way is plumbed.

That is part of your plumbing problem.

The other issues include that the boilers should be plumbed in series not parallel UNLESS there is a temperature balancing circulator between the two boilers.

It all depends on whether you want to lower the triple aquastat settings for the system to ride out the winter and then fix the mess in the off
season or fix it now as you need a to have a B+G or TACO representative look at your octopus of a system.

I'm not sure I see anything here related to the problem.

 

[maple1]

I'm not sure I see anything here related to the problem.

You are not alone.

 

[velvetfoot]

The 300 psi rating on the Zone Sentry is a max pressure rating, not the shutoff pressure. that bal valve type ZV probably has a 100 psi or so shutoff. Plenty for any hydronic system.

Most spring return type zone valves have a much lower shut off pressure.

I think the Zone Sentry is pretty nice too as far as low power. I've read people complain that the ball hole diameter is small if you get a larger valve. My complaint, as I recall, is that it would've been very easy to make it NO or NC, but they didn't.

 

[Bob Rohr]

The multiple expansion tanks present multiple PONPC and should be avoided. Some times two tanks are used if the boiler can be isolated, with the tank, from the system.

One large expansion tank would be preferred and at the location shown.

Another problem with that drawing is the boiler pumps are pumping towards the exp tanks, that is a problem, always pump away so the pumps add their delta P to the system. Dan Holohan has been preaching Pumping Away for 20 years now, but its importance still confuses some designers

I prefer parallal boiler piping to series as series flows heat through an un-fired boiler. Only if you have a tankless coil in the fossil fired boiler would I series it with a wood boiler.

That drawing has been around for sometime now and has many hydronic no-nos in my opinion.

 

[velvetfoot]

I think the Zone Sentry is pretty nice too as far as low power. I've read people complain that the ball hole diameter is small if you get a larger valve. My complaint, as I recall, is that it would've been very easy to make it NO or NC, but they didn't.

I swear the post was there! LOL

 

[Bob Rohr]

Here is what I feel shows a viable way to parallel boilers to storage and buffer tanks. Same concept as one of the above, with some additional detail info.

I feel both boilers wood and gas or oil need return temperature protection, shown as 3 way thermostatic valves unless they are condensing type
boilers.

I consider this a two pipe buffer tank and a key detail is the large diameter connection headers into the tank. Those act a low loss headers or hydroseparators. They need to handle the entire potential flow of the entire system, with low pressure drop to prevent un-wanted flow.

I put some random flow rates to show how pipe sizing plays into design. If ever both boilers could run at the same time, perhaps if the wood boiler fails to keep up, the piping needs to accommodate that combined flow rate.

So two boilers at 10 gpm (20 gpm) header into a 1-1/4 pipe.

The header into the tank could see that 20 gpm flow plus all the distribution (15 gpm) flow rate. In this example 2-1/2 or 3" would provide flow for a potential 35 gpm flow.

A single expansion tank, properly sized pipes into the buffer tank stack. the entire tank(s) become the point of no pressure change PONPC. As such, every pump in the drawing "pumps away" from that PONPC. They add their delta P (pressure increase) to the system.

The distribution pump to the heat emitters would be a delta P pump, like a Grundfos Alpha or correctly sized ∆P circulator. That would eliminate over pumping those circuits,when small loads turn on and off.

 

[leon]

Thank you Bob, As I said he has a mess on his hands with that plumbing.
I will tell Dan Holohan you said hello when I tell him of my success with
the replacement Honeywell L8124L1011 controls on my keystoker-KAA-4-1

 

[huffdawg]

I think I would deactivate the load pump and see what happens first before doing any drastic piping changes,especially in the midst of heating season . Also making sure you have flow checks in your zone circs.

 

[lazycoyote]

Since you use all pumps, not zone valves, you may be pushing hot water backwards through the other zones. Is there check valves on the other zones to prevent this?

Sent from my ONE A2001 using Tapatalk