Category Archives: Heating

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

Commissioning Authority

I have been in the HVAC Industry for 30 years and the amount of nonsense that goes on in any given project, never ceases to amaze me. Projects that run ridiculously over budget, technical equipment not functioning as designed, engineers that lower the bar to account for mistakes, and numerous other deficiencies that are passed on to owners.
The Construction Industry has changed extensively over the past 10 years, building structures and its systems are more complex. Systems such as, Communication Networks, Computer Servers, Surveillance Equipment, Building Automation, Sprinklers, Fire Alarms, tighter building envelops and complicated HVAC to mention a few. Added to this mix, are many new building codes that demand higher efficiency and stricter safety requirements. All these changes necessitate a higher level of skill which is increasingly difficult to hire as the skilled labour pool continues to shrink.

During this same time period, I have seen millions spent poorly and millions, needlessly added in future operating cost. Many owners and tenants have been disappointed to put it mildly. Had there been better planning in the beginning, a little more watch over the work site, during construction and proper commissioning on completions, a large amount of this money, could have been saved or, at the very least, better invested. Many new tenants and owners, would be much happier if they got what they paid for, instead of being stuck unexpected additional costs.

dirty filter-3
Heating Loop side stream filters

For example, this image is a water filter from a hydronic system. The building was less than 3 years old and there are serious mechanical issues. The mechanical system likely cost a million+ and, a particular filter was specified but never installed. The filter housing is worth $100.00 and was installed on the heating loop, afterwards. It was in place for about 2 hours before being pried from the filter housing. The muck on the filter is mostly iron combined with other contaminates. Some of the muck has been caught in the filter, much more can be found in every bearing, pump, sensor, valve, boiler and heat exchanger in this building. It will be almost impossible, to completely remove the material, the best you can do is to reduce it. It will cause damage to this mechanical system, for years to come and should have never been allowed to occur in the first place. The missing filter was not the cause of these issues but would have reduced the damage. In this case, the developer had a reputable design team, an experienced general contractor, and basic commissioning at the end of the project. So why did this problem occur and how would you prevent it from occurring again?

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