Add a zone to baseboard system

JohnnyHome

I am finishing my basement and before I close everything up I was thinking about adding a zone on the bottom floor. It is baseboard heating with one zone for the top floor and one for the bottom. The den on the bottom floor is always cold I assume because it is the last room in the run. It happens to be above the boiler so everything will be easy access. 

From the picture… looks like there is one main pump on the return on lower left. Then on the upper right are two valves controlled by the two separate thermostats. 

It looks “easier than I thought” to just add a third return and a send. But not sure about the single pump. 

Are there any suggestions to be more efficient?

hot_rod

On the return you have a plugged tee, add a nipple and ell there. Ball valve and purge valve to match the others
The supply side doesn’t look like it has a spare connection to add a 3rd zone valve.

reedevery

And for the supply, remove the relief valve, add a tee and nipple for a third zone valve.

MarkMurf

Looks easy peasy . The 15-58 circ pump is already handling the load, no poblem.Perhaps yer first floor zone is a bit too long ? In which case, to split the zone is exactly the answer . And while I was at it, my personal preference, now-a-days, being a life-long service type trouble-shooter, would be to change to Taco ESP zone valves.They are far more easily trouble-shot, what with their modular connections, indicator lights, and clear opened or closed position. You don't even need a pocket screw driver to change a faulty head ! And being an old oil burner man, that's a nicely done, neat little system you've got there 👍👌🔥 ! !

JAdams

I suggest doing a heat load calculation before proceeding. Just because the den is at the end of the loop doesn't mean it should be cold. If sized properly, it should heat as well as the other rooms.

hot1

On a different topic; looks like exp tank for dom hot water is installed incorrectly. Bottom of tank should be parallel to basement floor. Surprised no one mentioned air in the cold loop.

Leonc

One thought to consider is that you don't necessarily need to have a whole new zone if your main problem is that one room is not balanced with the rest of the zone.
This option might be more time/effort/money, but depending on how the individual baseboards are piped, you may be able to change that around to something that offers more control of the flow between the baseboards that share the same zone.

I did this two years ago, when I had one circulator that fed a single large pipe, that then branched off into smaller pipes to feed each room. The room that was farthest away from the large main pipe would never warm up at the same rate as the others because the smaller branch piping was so much longer than the other rooms.
I took out the main pipe and piped each room directly from a manifold (https://www.caleffi.com/en-us/assembly-668-caleffi-6686c5s1a) using pex-al-pex, and now that cold room is as warm as the rest. I have control over which rooms get more/less flow compared to the room that has the thermostat for the zone.

Again, this option may be more work compared to a new zone, but I didn't want you to lock yourself into adding a zone without at least hearing this option. If there are other cold/hot rooms in that same zone, this gives you the ability to balance it.

Intplm.

@JohnnyHome
Much of the advice above is very good except for one thing.....removing the relief valve. DON'T DO THAT!
to add to the zone. Unless of course you know enough to re-install it.

When you do add the third zone you will be dumping the water out of the system.

After doing a heat loss calculation to properly size the conditioned space I would also change a few things.
Its a good time to do this because the system will be down for some time and this will avoid having to do them in the future.

Get rid of the two expansion tanks and replace them with one properly sized expansion tank.
Remove the leaking air scoop and top hat air vent and replace it with a micro bubble air separator.

These things will help with the systems performance and help remove some future repairs that will surely come in the near future.

Please post some before and after pics.

Kickstand55

There's a lot going on here before you consider adding a zone. I never want my customers or anyone for that matter to spend short money on something that's going to come back and bite them later. However, I let them make all the decisions based on suggestions only.
Furthermore, if you are hiring a contractor to perform repairs, alterations or installations, keep all this in mind. If you are doing the work yourself, do lots of homework and planning before beginning.
Here's what to consider:
*How long do plan on living there? You might consider an upgrade to a more efficient dependable system.
*The age, condition and quality of the existing boiler. This boiler is a price leader, dry base firebox type boiler and being built in England for export to the US has had it's issues, no longer produced to my knowledge and probably 25+/- years old at this point. Being a dry base firebox boiler, many of them have experienced liner collapse and burn out the metal base in the back.
Check the back of the boiler near the floor for overheating and paint missing from back wall.
*I see signs of a past leak at the air vent on the air scoop leaving mineral deposits behind. This could be an indication of hard water and/or chlorides in the water source. Worth having a water test done at a certified laboratory in your area. Boiler manufacturers now state water quality conditions in their installation literature. Best if the pH is above 7 to around 11, chlorides, (chlorine) less than 30 parts per million, hardness less than 9 grains. Water conditioning can help. Be aware of salt-based conditioners. They add conductivity to the water. Adding corrosion inhibitor and adjusting the pH can help.
*The piping on the boiler will need minor modifications to accommodate your plan. Do consider an extra zone for a future indirect hot water heater with a zone control panel to include priority zone for the HW tank if you decide to keep this boiler.
*As before, splitting a single zone may be an advantage if the piping is very long. By the time the hot water gets to the last part of the piping it may have lost mush of it's heat value and be ineffective.
*Replace old gaskets and washer type valves as the rubber seal may not hold water.
*Note: The tankless heater does not have a mixing valve or a temperature/pressure relief valve.
These are code and mush needed to prevent scalding and excessive pressure build up.
*The domestic expansion tank, (the blue one), is in a horizontal position. When, not if, it becomes waterlogged, there's a great chance it will break the copper piping causing a leak.
Best to mount it on a wall with a bracket for support to include a shut off valve.
*Always check the heating expansion tank for proper pre-charge when the system pressure is brought to atmospheric. Also check the boiler pressure relief valve while under pressure pre manufactures instructions.
Granted, there's been a lot of dialogue here, but it's for your benefit.

Dave

Stet

Pretty Simple ! As one mentioned, you remove the plug on the return and add a return. Cut in a third zone valve, and tie it in with its own thermostat. I would add a tempering valve on that tankless piping!

EBEBRATT-Ed

Take one of the elbows on the supply befor the existing zone valve and install a tee in its place and tie in the third zone their.

UncleAl

Based on a blow up of the photo, it looks like the zone valves are on the return flow.  The air separator looks like it has a flow arrow pointing away from the zone valves, which would have the expansion tank on the pump inlet, as recommended.  Also the valves are connected with a bullhead tee, which is acceptable on return lines but not supply piping.  I could not see the flow arrows on the zone valves.  Normally supply is taken from the top boiler connection and returned the the lower boiler connection.  It would not be the first time someone installed a replacement pump upside down.  You can get proper piping schematics from any boiler mfgr on line.  I would recommend you get a service visit from a qualified boiler tech and ask their opinion on your equipment and adding a zone.  

MikeDurigon

Pump is on the return piping to the boiler, is that correct. It looks like the supply tee is bullheaded. That is not good piping practise as i believe due to turbulence one side will not flow thru the tee.

JMGotts

I believe it's cold because your aqua stat setting for winter is incorrect. You have it set for the typical "default" 180/160. Set the high limit to 200 and see if it resolves your issue. People have a tendency to
freak when they see that temperature setting, but as you know, it works the same way as a car radiator under pressure, it raises the boiling point. More people (I'd say the majority) use that setting of 180/160/20 as a standard with no clue. You're probably short cycling the heating system, it never gets the baseboard hot enough in that room. And BTW, I recently got educated by the master himself on those settings. Although I can get away with a lower set value, it works for me. Look for my post on the "Controls" section of posts. PS...you'd have to raise the low limit as well, say to 180.
https://forum.heatinghelp.com/discussion/195888/my-honeywell-l8124c-r8184g4009-operation-question#latest

Stet

Intplm. said:

@JohnnyHome


Get rid of the two expansion tanks and replace them with one properly sized expansion tank.
Remove the leaking air scoop and top hat air vent and replace it with a micro bubble air separator.



I believe that one of those tanks is connected to the domestic water supply to the tankless coil.

Stet

UncleAl said:

Based on a blow up of the photo, it looks like the zone valves are on the return flow.

The zone valves are on the supply side as is the air scoop. As one person mentioned, remove one of the 1" 90s on the supply side and install a 1 x 3/4 x 3/4 tee and add your 3rd zone valve. The return already has a 3/4" plug you can use for the return. You can spend a lot or a little. If fairly old, I would replace the fast fill, back flow, and pressure relief valve too. Make sure the expansion tank is charged. These componants are the ones that will end up being a thorn in your side if you don't correct.

We recently look at a job one town over. A boiler exploded. Not from the fuel.The burner never shut off. The relief valve was completely plugged with rust and scale. The explosion blew out the three framed walls of the boiler room and popped up the flooring above it about 2 inches. The gas piping for the boiler and the gas water heater snapped out of the fittings. ALWAYS check old relief valves.

Intplm.

Stet said:

Intplm. said:

@JohnnyHome


Get rid of the two expansion tanks and replace them with one properly sized expansion tank.
Remove the leaking air scoop and top hat air vent and replace it with a micro bubble air separator.



I believe that one of those tanks is connected to the domestic water supply to the tankless coil.

Hard to tell from the pic but now that you mention it.
@JohnnyHome. Look into that blue tanks purpose. Relocate it either way. Not the best place or position for that tank.