Boiler Zoning

dhaselhorst

I have a traditional hot water system with cast iron radiators in a two story house old drafty house. The upstairs is always hot and the downstaris cool. I have tried adjusting the rad valves, but can never get a good compromise.

I was thinking of zoning the system with thermostatic control valves on each radiator. The idea would be that as the room temp reaches the appropriate point the thermostatic valve would close and and the heat would go to where its needed. The problem is I'm not sure what type of boiler controller to use. I would like to put one t-stat upstairs and one down with a 'smart' controller running the boiler and the pump. I have seen similar 2 zone forced air controllers with dampers that even have an additional fan run time circuit to move hot air from upstairs to down.

I would think there would be something similar for hydronic with remote thermostatic valves, independent automatic valves, not wired, and a couple of remote tstats to send the request for heat in. Additional benefits would be additional circulator pump run time after a heat cycle to move remaining warm water to the requesting rads.

Are you guys aware of any simple hydronic controllers that would work in this situation. I don't believed I'm plumbed correctly for independent, wired zones, I have one big loop running to all rads.

Thanks for the help

-Darin

Mike Kraft

Darin,

How old and drafty is the home?Is the water being moved with a pump?Is the distribution piping a two pipe or single pipe?What model pump do you have?

Here is a link you can cut and paste to your browser.Click on the TRV link for a description.

http://www.danfossheating.com/products/heating/heating.htm

Then do yourself a favor and cut and paste this one and reead it.Excellent info.

http://www.heatinghelp.com/newsletter.cfm?Id=119

cheese

Mark J Strawcutter

changes in phases

You could start by putting TRVs on the second floor radiators and leaving the boiler control/thermostat as-is. When they all close down you may find you need a differential pressure bypass to avoid damaging the circulator.

Next step could be to put TRVs on the rest of the radiators, switch to constant circulation, and control the boiler with outdoor reset. This would definitely require a differential pressure bypass. You end up with each room on it's own zone, water ready at just the right temp for when a TRV opens.

Mark

dhaselhorst

Thanks for the quick response.


The house was built in the 40s. There is a circulator pump. The distribution piping has one main (2 inch?) line to each rad with a 3/4 tee inlet and outlet with a valve. The pump is a Taco 007-F3-W Cartridge Circulator


> How old and drafty is the home?Is the water being

> moved with a pump?Is the distribution piping a

> two pipe or single pipe?What model pump do you

> have?

>

> Here is a link you can cut and paste to

> your browser.Click on the TRV link for a

> description.

>

> http://www.danfossheating.com/prod

> ucts/heating/heating.htm

>

> Then do yourself a

> favor and cut and paste this one and reead

> it.Excellent

> info.

>

> http://www.heatinghelp.com/newsletter.cfm

> ?Id=119

>

> cheese

dhaselhorst

Mark,

I like the idea of the incremental step of putting the TRV valves on the second floor. Seems like a logical next step. One concern about leaving the conroller and tstat as is, is that I have a fireplace one the first floor. The only time the upstairs gets cold is when I have a fire going. The lower room is fine. The tstat is at temp and the upstairs starts getting cold.


What is required for constant circulation? Does that involve running the pump 100% of the time and somehow keeping the circulating water at a constant temp? It there a new controller involved, or simply hardwiring the pump closed?? Outdoor reset??

Thanks for the insight.

-Darin




> You could start by putting TRVs on the second

> floor radiators and leaving the boiler

> control/thermostat as-is. When they all close

> down you may find you need a differential

> pressure bypass to avoid damaging the

> circulator.

>

> Next step could be to put TRVs on

> the rest of the radiators, switch to constant

> circulation, and control the boiler with outdoor

> reset. This would definitely require a

> differential pressure bypass. You end up with

> each room on it's own zone, water ready at just

> the right temp for when a TRV opens.

>

> Mark

Mark J Strawcutter

single pipe mains?

Radiator inlet and outlet connect to same large main pipe?

Radiator valve is on inlet or outlet?

Mark

Mark J Strawcutter

I thought the upstairs was always hot?

Move the thermostat to a downstairs room without the fireplace.

As it's name suggests, constant circulation does indeed involve running the circulator "all" the time. While there are lots of different features and subtleties in the various outdoor reset controllers, the basic idea is the same - to have the water just hot enough to replace the heat lost by the building.

An outdoor sensor tells the control how cold it is outside, and the control varies the water temperature accordingly (ie it "resets" the high limit based on outdoor temp - hence the name "outdoor reset"). When it's warmer out you don't need the circulating water to be as hot as when it's really cold out.

Mark

Art Pittaway

Look at those tee's

and see if some of them are shaped different. Longer on one side than on the other or if the have an arrow or grooved ring on one end. If so, those are not tee's, they are mono-flo or diverter fittings and you need to be careful how restricted the TRV's are or you may wind up with no heat on the second floor. Basicly they divert a little of the flow to or from the radiator. These systems depend on velocity to work and don't have a lot of pressure to force through a control valve. You may find some info on the Bell&Gosset web site.
Art

dhaselhorst

Radiator inlet and outlet on same large main pipe. I believe the valves are on the input side.


> Radiator inlet and outlet connect to same large

> main pipe?

>

> Radiator valve is on inlet or

> outlet?

>

> Mark

dhaselhorst

I do believe the 'tees' are directional flow fittings. I did intall one TRV on baseboard and had good results with it. The cast iron base board gets as hot as other radiators in the house.


> and see if some of them are shaped different.

> Longer on one side than on the other or if the

> have an arrow or grooved ring on one end. If so,

> those are not tee's, they are mono-flo or

> diverter fittings and you need to be careful how

> restricted the TRV's are or you may wind up with

> no heat on the second floor. Basicly they divert

> a little of the flow to or from the radiator.

> These systems depend on velocity to work and

> don't have a lot of pressure to force through a

> control valve. You may find some info on the

> Bell&Gosset web site. Art

dhaselhorst

Mark,

Thanks for the input. Where would I find specs. for these type of controllers. I'm thinking a potential solution would be TRV upstairs as step 1 and a continuous flow setback controller as step 2.

It would be great if I could have two thermostats 'in parallel' so to speak that either one could call for heat, although this sounds like I would need TRVs on both floors.

Do you know where I could find specs. or documentation on smarter types of hydronic controllers. It seems the expertise in Northern VA is somewhat lean.

-Darin

heatboy

In Northern Virginia.........

you might want to give Dan Foley from Foley Mechanical a call.

Alexandria, VA - Dan Foley - Foley Mechanical, Inc. , 5010 Grimm Dr. ,Alexandria, VA 22304,
phone/fax: (703)751-3288, e-mail: dfoley50@comcast.net

When it comes to your issue, start by modulating the water temps in your radiators with a reset control and 4-way. After the system is running and the curve is dialed in, you can add TRVs to just the radiators (if any) that over heat.

Warm Regards,

hb

"Expert in Silent Warmth"™

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Mike Kraft

Darin

You are getting great advice and suggestions.Definitely take heatboys advice and contact Dan.He is just what you need.Here is more info for you to read.Cut and paste.

http://www.heatinghelp.com/newsletter.cfm?Id=28

cheese

Steamhead

Also look at

http://www.heatinghelp.com/newsletter.cfm?Id=125

This is the one with the chart.

Thanks, Cheese.




To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Nobby

If the system is a gravity conversion is there a possiblity that there are reduction orifices still in the upstairs radiator piping at the valves.
Just a thought.

Mark J Strawcutter

controllers

> Thanks for the input. Where would I

> find specs. for these type of controllers. I'm

> thinking a potential solution would be TRV

> upstairs as step 1 and a continuous flow setback

> controller as step 2.



"setback" has a different meaning in the heating trade than "outdoor reset".

> It would be great if I

> could have two thermostats 'in parallel' so to

> speak that either one could call for heat,

> although this sounds like I would need TRVs on

> both floors.



With an outdoor reset controller you don't really need any thermostats - the TRVs are the thermostats, one for each radiator.

> Do you know where I could find

> specs. or documentation on smarter types of

> hydronic controllers.



Tekmar and Honeywell both make outdoor reset controls. Tekmar has models with more bells and whistles than you could ever want :-)

I agree with others about contacting Dan Foley

Either a 4-way or primary/secondary pumping would be a good way to modulate your water temp while protecting your boiler from thermal shock and condensation. I favor TRVs on all radiators/baseboards for better flexability.

Mark

Mark J Strawcutter

monoflo

With a monoflo/diverter system I don't think you'll need a differential pressure bypass if you put TRVs everywhere.

While I like Danfoss stuff a lot (and am using their TRVs in my house) I'd probably look at other brands with less pressure drop for use with a monoflo system.

Mark

dhaselhorst

HB,

Thanks for the response. You guys have been great with the suggestions. Sorry for all the questions, I'm just trying to come up to speed on the terms. I think I now know what a reset control is, allowing you to adjust the water temp base on the outside temp. Whats a 4-way?


> When it comes to your issue, start by modulating

> the water temps in your radiators with a reset

> control and 4-way. After the system is running

> and the curve is dialed in, you can add TRVs to

> just the radiators (if any) that over

> heat.

>

> Warm Regards,

>

> hb

>

> "Expert in Silent

> Warmth"™

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 103&Step=30"_To Learn More About This Contractor,

> Click Here to Visit Their Ad in "Find A

> Contractor"_/A_

Mark J Strawcutter

you really should

get a copy of "Pumping Away" from the books&more section here at heatinghelp.com.

Next try "how come?" then "primary secondary pumping made easy"

Fascinating stuff.

Mark

dhaselhorst

I ordered a copy of the first two today. Thanks!

dhaselhorst

I gave Dan a call. Thanks for the referal.

heatboy

4-way

Darin,

A 4-way mixing valve is the component that serves as the mixing point of the system. The high temperature boiler water and low water temperature radiant water meet. The 4-way has a vane that is operated by an actuator (motor) that gets it’s signal (24 or 120 VAC are the norm) to open or close from the reset control. The control measures the outdoor temperature and adjusts supply water temperatures to meet the load by opening and closing the valve. Depending upon your system configuration, there will be an outside, supply, return and possibly indoor sensors that relay information to the control. There are several manufacturers that offer these systems. Danfoss, Tekmar, Viessmann are a few that do. Sizing and piping of the 4-way is critical to make the system work comfortably and efficiently. Each manufacturers valve has it’s own characteristics so follow there sizing instructions. Rob Bean from Danfoss has forgotten more about things like this than I’ll ever know and maybe he will chime in on the subject.

Warm Regards,

hb

"Expert in Silent Warmth"™

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"