A Bit About Zoning A Hot Water Heating System

Just how it all works

Properly piped multi zoned forced hot water heating systemHow to add a zone to a hot water baseboard heating system, is something many homeowners need to know.

First of all they want to know if it can be done. Secondly, how much will it cost. The third and last question is of course, how to do it.

To simplify the answer to all three questions, is to explain how the system works to start with. Where the piping goes when it leaves the boiler and all the components that help to make the system work. A basic understanding is required before it all makes sense so this article must begin by explaining the functioning parts and the order in which the operation takes place.

Without a good understanding of whats going on when you turn up that thermostat, you will find it very hard to follow along. Hot water heating systems are really quite simple and easy to build. There are ready-made parts that are available to simplify the job.

The following section will walk the average homeowner through the basic operating procedure and the series of operation that takes place when there is a call for heat.

Time Tested Honeywell Zone Valves for Reliability

Simply the most popular valve out there today.

Amazon Price: $190.05 $67.80 Buy Now
(price as of May 26, 2014)
The reason this type of valve comes so highly recommended is because they have a history of being the most reliable valve on the market today. They are also very easy to service as well.

This Pump is Perfect for Adding a Residential Zone

Taco stands tall in the pump game

Taco 007-F5-7IFC Cast Iron Cartridge Circulator Pump
Amazon Price: $85.00 Buy Now
(price as of May 26, 2014)
One of the most popular pumps, used by plumbers and heating service tech's for many years.Taco has shown over time to make reliable products with easy servicing features

Hot Water Heating Boilers

The heart of the system

The boiler is the heart of any hot water heating system. This is where all the action happens. Boilers are used by the system to heat the water that will transfer the energy to the area being heated.

Boilers use many types of fuel to heat the water. Some are fired by oil and some use natural gas. Propane units are available as well as boilers that use electricity. There are even wood fired boilers. All of these fuels are doing the same job. They are heating water within the boiler.

Conventional style boilers over the years, held large volumes of water and were very inefficient. This was due in part to the fact that no matter how much, or how little heating was called for, the entire system would need to be brought up to temperature and then the water was circulated through whatever radiation was used and the transfer finally took place.

Today's modern units are far smarter than their ancestors. New innovations and advancements in technology have come to market and newer units hold very little water. New and improved circulation techniques have made it possible to heat only the minimal amount of water to satisfy only the existing call for heat. This has eliminated a great deal of wasted energy.

If you have a traditional boiler, it's probably a free-standing unit with an octopus like piping system coming from every side.

If you have a newer more advanced unit, it may be found hanging on the wall with a very simple and organized piping system around it. Either way the series of operation and what actually happens when you turn up that thermostat is pretty much the same for all types of hot water heating systems.


Fresh Auto-Vents Will Keep The Air Out

An inexpensive way to keep your system air free.

400 TACO 1/8 INCH air VENT 150PSI
Amazon Price: $10.70 Buy Now
(price as of May 26, 2014)
This is another reliable taco product that's worth it's weight in gold.

Full Port Ball Valves Allow Full Flow

Stick to the name brand valves

Homewerks 114-4-34-34 No-Lead Full Port Packing Gland Ball Valve with 1/4-Turn, Solder x Solder, Brass, 3/4-Inch
Amazon Price: $15.47 Buy Now
(price as of May 26, 2014)
Buying inexpensive valves from an inferior manufacturer can save you money On the initial installation, but in the long run when they start to leak the savings will be quickly lost.

Zone Components

And What They All Do

Any zone of hot water heating will begin at the boiler and head out through a manifold tee. That line takes heated boiler water and sends it through a pipe to radiation remotely located, in the area we're trying to heat.

As the piping tees off for the zone from the boiler feed manifold, it will need a few extras to keep things running smoothly and efficiently. The following list has all of these hot water heating system components.

Ball valves

Purge valves/boiler drains

A Circulator pump, or a zone valve, depending on the system design

A flow check valve

Automatic air vents

Circulator pumps are used in some systems on each zone. Other systems will have one larger circulator pump and a single zone valve for each zone. Usually when adding a zone to an existing system cost factors can come into play. Zone valves are cheaper to install and they are an efficient way to split up a hot water heating system.

The preferred method and a more durable way to design the system is to incorporate an inline circulator pump into the loop as the feed leaves the boiler. A ball valve is recommended on both sides of the pump or zone valve for easy servicing later. This helps us by making it simple to work on the part without draining the entire system.

The purge setup is installed near the pump, and consists of a ball valve and a purge valve, or boiler drain, close together. By shutting off the ball valve we can push water out the feed and through the loop or zone and back to the boiler until it's discharged through a boiler drain along with any air that's within the system.

An easy way to make sure the air is out of the system is to put the end of your hose into a bucket and watch for bubbles. When the bubbles are gone the system is air free. Use ball valves to reverse the flow out the drain and run it both ways to make sure all the air is eliminated.

After the purge setup, a flowcheck valve will be installed to prevent gravity feeding of the hot water when another zone is calling. Once we have a flow check, some will install another shutoff valve but it's not required.

Piping now runs to radiation, be it baseboard heating, or radiant tubing in the floor. Convector heaters and fan units. Many kinds of radiation exist on the market today. All of them take the heated water and transfer it either directly or indirectly into the room we're heating.

After flowing through the radiation, the water is piped back to the boiler. Another valve should be installed to isolate the boiler on the return side. All of these shutoff valves are great to have down the road when a part needs servicing, or a new pump must be installed, they can cut the service time in half in some cases.

So basically we have just tapped off the boiler and run a pipe through the room we're heating and back to the boiler. We've installed a few components along the way and our zone is ready to purge out. 

A thermostat must be installed and wiring to the boilers relay system. Thermostat wiring varies from two wires for a simple on off thermostat to ten wires for complex systems that have heat pumps and air conditioning. Schematics for each system should be on the boiler door or the individual control covers. 

A relay must be added for each zone we add. This electrical device takes the message from the thermostat and calls the boiler and the zone valve, or pump for that individual zone. Each zone must have its own relay.

It's strongly recommended that a competent electrician be employed to take care of wiring the added zone. If you understand schematics then you'll be able to wire your new zone, if you don't then I can't teach you in this short article.

This article is giving you the basics for adding a zone of heating to a hot water heating system.

If you are interested in Understanding Hot Water Heating Systems better, you can scroll my articles at the top right in my signature box or check out my e-book.


All Multi Zone Units Need Flow Checks

Keep the heat

Taco 219-5 Flo Check, Bronze
Amazon Price: $38.49 Buy Now
(price as of May 26, 2014)
Hot water rises on its own so we need a flow check to stop the flow when our new zone is not calling.