Older houses leaked and, to a degree, are uncomfortable and energy inefficient.  We may think a cold room is standard in houses or a wood boiler needs to heat our house to 26C in the winter. We get use to opening windows in winter to get some fresh air in the house, or even cool down an overheated house.

Radiant heating on the lake.
Radiant heating on the lake.


This is number one, so I put it first.  We live in our basements as much as we live on our main floors now.  So the days of cold basements are done.  You want comfortable temperatures everywhere in the house.


Whether you have radiant or forced air, you want to be comfortable.  Zoning allows you to use one source of heating or cooling to meet the different temperature requirements throughout the house.


Everything should be efficient.

For radiant – the boiler, pumps, piping, and distribution needs to take care to ensure high efficiency.  This means looking at variable speed pumps; adequate pipe sizing to reduce flow restrictions; efficient boilers; and a distribution system layout that allows you to heat with the minimum temperature water you can.

For air systems, you basically want the same – adequate sized ducting for air flows; proper returns; variable speed blowers; and staging equipment to match uneven cooling and heating loads.


This is not your heating and cooling system.  Codes require a constant fresh air ventilation for buildings.  There are workarounds that are poor choices, but are available to the budget conscious.  Really you need to be looking at heat recovery ventilators or equivalent.  Read the first sentence of this paragraph again.


Controls can help a system and they can get very complex very quickly.  At their basic they just turn equipment on/off without us being around.

We can start adding basic features such as setbacks and weekly scheduling.  We can also get more complex with remote controlling and monitoring; weather monitoring and predictive heating or cooling; and zone controls.

Ideally, controls should be like your system.  You should not have to worry about it once it is set up.


Overall you want the ambient temperature of the house and all its areas to be comfortable for you to live in.  Secondly, you want lower energy bills.

It does not matter whether it is geothermal, a propane boiler, or a gas furnace – all systems can get you there.

We asked Uponor to put together a residential vault and they responded.

VAult1 (Medium) Vault2 (Medium)

We’ll be installing this 6-on setup on a client’s property this spring.

A fair amount of our work is not really “geothermal”.  In this case, we are working with an existing boiler hydronic system converted to geothermal.

The initial conversion functioned, but had poor climate control.  Heat wasn’t all that adequate with the original staple up PEX spacing and there was no cooling option.

So, the plan is to work with fan convectors, and we’ll get to that in a follow-up post.

But first we took the opportunity to fix the existing boiler room plumbing.


A couple of items were taken care of besides tidying up the years of fixes:

  • constant differential pressure load pumps were installed to allow zoning flows to be controlled simply and effectively
  • remote REHAU headers (not shown) are installed to allow the future fan convector installation (heating and cooling)
  • makeup water done properly (pressure reducing valve, air separator, expansion tank, backflow preventor)

Now we have the proper foundation in which to move some heat and cool around the house.

This particular posting is a reference drawing on a typical plumbing layout for a water to water heat pump, hydronic fan coil, radiant floor, and domestic hot water support.

There are a number of variations likely in the plumbing:

– the domestic hot water can be a zone off the initial load plumbing as it runs through a heat exchanger.  A pump would be required on either side of the heat exchanger.

– you may only have one hot water tank, in which the primary source of heat may/may not do most of the work and the heat pump adds little support.

– you may not have multiple pumps, but just one pump and a combination number of zone valves opening to their zones.

– your supply/return for each zone may be different.

A common water to water heat pump layout for a DES system.
A common water to water heat pump layout for a DES system.


This comes up often enough in our work that it is worth a post.

When two or more heat pumps are pumped in parallel without thought given to flow, you can run in to some issues.  Look at this figure:

Short Looping
Short Looping

If  only one heat pump comes on the flow can go backwards through the second heat pump and return directly to the one heat pump.  This can be on either the source or load side of plumbing (if radiant). Worse yet, this may only occur intermittently.  I’ve seen systems in place for years that have been plumbed this way.  It causes problems “sometimes” and may or may not be noticed by the owners.  But it does cause some extra wear and tear on the units due to the extreme water temperatures that they are now exposed to.

The simplest way to solve the problem is to use check valves on the supply side of the heat pumps.

Normal Flow
Normal Flow

There are other options with pump locations, solenoid valves, and plumbing layout.

I have just shown enough to get the concept across as it does put us in a tough position if we end up servicing such a system.  There is not much reason to fix something wrong with the heat pumps until one fixes the plumbing.

With a very busy fall, we have been travelling a lot and not necessarily working in town.

A client was getting worried about his geoexchange air/radiant system as the cold weather approached.  I started off the texting early Saturday morning as I did not want to wake them.

I admit I was happy to sort this out without loading up on a Saturday morning.


This is not really about a 10-ton header, this is about the issues one needs to think about in header design.

This is a picture of a 10-ton header we built.

10 Circuit Header
10 Circuit Header


Now the header is for a residential property, with a bunch of (expensive) ball valves fused in line. Commercially, an engineer would likely specify the design with a focus on flow optimization and may end up with the same layout. For residential, one would commonly bury the header after pressure testing.

In this case, we also need to think about service calls. It is highly unlikely that a service company is going to show up at a residential property with a 5hp purge cart. Most of us typically carry 1.5 to 2 hp purge carts.

So you spend a bit more money up front allowing one to isolate individual circuits for future maintenance. In the end, we can purge and setup this system with the existing circulating pumps. We don’t even need to take the purge cart out of the truck.


Yes, we take service calls.  There are a lot of geoexchange systems in our area that no longer have the support of the original installer.  I’ll leave it at that.

But sometimes we do wish we did not take the call.  Joking.  Just some days you learn more than you want.

Here is an example.


That is a really burnt out compressor capacitor.  Very burnt out upon closer inspection.


It also managed to start a small fire that melted more wires.


In the end we replaced the control board, capacitor, main contactor, and the transformer on the unit.


Back to working.

Now who wants to help me sort out these low voltage controls?

20130628_150559[1] 20130628_154424[1]

A recently completed mechanical room with two Waterfurnace water-water heat pumps, Tekmar controls, Wilo loop pump, and the usual mechanics.  This is on 16-18′ of wall space.

Apologies for the photo quality as this is a panorama (distortion) taken on a cell phone (lower quality).


Mechanical Room Panorama