Cheakamus Crossing Fall Maintenance

Many residents in the Cheakamus Crossing, ask about the maintenance required for their heat pumps. These heat pumps, do not have items that require annual service, there are no filters to change, motors to oil or belts to replace. Having the units inspected every year is not necessary but couldn’t hurt, if inspected by a qualified refrigeration technician. Anyone else, and it just may hurt, the heat pump and the wallet. A qualified technician can identify hidden issues such as overheating, control problems, circulation problems and other issues, preventing future issues.

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Buffer Tank – Heat Pump – Hot Water Tank

In the past, there have been number of problems which had nothing to do with maintenance. Most of which were manufacturer issues with the equipment, installation issues that have been corrected or operator issues.

The only, “maintenance type” item that has been an issue, is the cleaning of the load heat exchangers, the frequency of which is undetermined.

These units have run since the fall of 2008 and, several of these units have been tripping on high pressure. The load heat exchangers, that transfers heat from the refrigerant, to the heating water, have built up scale on the interior surfaces which cause the unit run higher pressures. These units trip on high pressure at 610 PSI. Pressures this high can do serious damage and is not something that can be resolved by a DIYer or unqualified service tech safely. If you see a red screen that reads E2 High pressure fault, call a qualified technician for service. Resetting the control, will restart the unit for a while but it will run hotter than normal. Resting the control multiple times can lead to compressor damage.

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Scale from Cheakamus Crossing heat pumps

There are no access valves on the heat exchanger which makes cleaning difficult and there is a limited number of choices for cleaning and treatment. The heat pump is used for potable water which places several restrictions on what treatment that can be used. If a potable water system, is even at risk of being contaminated, it is considered a serious issue and very expensive to resolve.

There are two other heat exchangers, one for the potable hot water and one the source water. It may be necessary to clean these heat exchangers as well in the future. Several source heat exchangers required cleaning, in the first two years of operation, due to DESS water quality issues, which has since been resolved.

The two storage tanks have aluminum anodes which will need to be replaced in a few years, even sooner if you live in the upper rise. This image was taken last year and shows some corrosion but will be several years before it needs to be replaced.

Image of anode in a hot water tank
Buffer tank anode

Buffer Tank Pump

Heating systems used in the Cheakamus Crossing development use radiant floor heating and fan coils. Water heated in the buffer tank is circulated by a three speed Grunfos pump. When the heating system first starts in the fall it is important to check for proper circulation. The circulation pump has not run for several months and there is a chance that air has built up and can prevent the pump from circulating water and cause the pump to fail.

Image of pump and PEX piping
Buffer Pump and PEX Piping

Turn up a few of the thermostats so several zones will call for heat. Within 5 minutes the pump should start. There may be some gurgling at the start but should stop after a few minutes.   The gurgling sound is from air in the system which is common in many of these units and difficult to completely eliminate.   There are automatic air bleeders installed on the heating system and an air scrubber of the heat pump circulation but do not always work. Some air bleeders are poorly placed or can fail if the vent plugs up.

Air trapped in the system will compress and prevent the water circulation. Without water moving through the pump it will over heat. There are several reasons why the pump can fail but air trapped in the pump has been an issue and happens most often at the beginning of the season or after the pump has been off for an extended period.

It is not obvious on these systems that water is circulating, it may sound like the pump is running but there may be little or no water circulating. You will need to remove the access panel on the first floor to see the radiant floors valve headers. Flow indicators on the top or bottom of the valve header should move on the zone valves that are open. If the actuator is raised and the pump is running, there should be movement on the flow indicator. If the actuator is down then the flow should be zero.

In floor heating
In floor heating

If there is no flow through the pump, the body of the pump will get very hot, too hot to hold your hand on it without burning. These pumps are fairly tough and can handle a little overheating, but if it is left to overheat for several hours will cook the bearings and the pump will have to be replaced.

If there is problem, then call a service technician to look at the system. They may be able to save the pump and correct the problem. There will be a reason for this problem, do not just replace the pump without identifying the issue. These pumps should last ten years or more. If the pump fails and issue is not corrected it will fail again. Some unit have already had this circulation pump replaced 3 times.

Call Western Technical System 604-849-0463