Nelson Mechanical Design was asked to examine an underperforming cooled water supply at a big home neglecting the south coast of Martha’s Vineyard. The setting up professional had actually been released due to their failure to get their system to work effectively and we were asked to carry out a cooled water rescue. Your home was unbearably moist and damp in the summer season– the cooling system was reaching the cooling setpoint in all 6 zones, however little to no dehumidification was taking place. We kept in mind right now that the discharge air temperature level was around 61 ° F at the 4 air handlers however the cooled water temperature level at the chillers was 44 ° F. Something was seriously jeopardizing the shipment of 44 ° F cooled water to the air handlers. No surprise your home was uneasy! Existing Equipment The home had 4 air handlers broke up into 6 zones and 3 5 load Daikin Altherma air to water heat pumps/chillers situated in a chiller pit 300 feet far from your house. Each of the 4 air handlers had actually a cooled water coil piped to a three-way zone valve and a warm water coil linked to a warm water loop served by 2 wall hung Buderus boilers. We identified that a person of the Altherma heat pumps/chillers had actually established a leakage over the winter season that wound up shorting out whatever within. To make complex the issue, we weren’t able to discover parts for it any longer. Nelson Mechanical Design Three Daikin Althermas in the chiller pit. There were no strategies or any documents of the system, however it appeared that the cooling load might be satisfied by 2 of the 3 heatpump. We collected that eventually the Daikin Altherma heatpump had actually supplied very first phase of heating which that had actually been deserted after the very first winter season. Do We Need to Rip This Open? Our next action was to go into the existing setup to comprehend the initial style and to find out where things went astray. As frequently occurs with these rescue jobs, the house owner had actually ended up being so annoyed with their persistent cooling problems and total absence of dehumidification in their villa that they permitted us to dissect their HVAC setup. We began digging and discovered great deals of concerns and great deals of style confusion. The heatpump in the remote chiller pit (300 feet away at the end of the rolling yard) were pleased on loop temperature, however your home was sweaty and unpleasant. Plainly the heatpump were not being linked to the dehumidification load. Chiller Pit Piping Issues The 3 heatpump in the chiller pit had their own internal circulators and were linked to a reverse return chiller loop. The 300 foot supply and return pipelines from the primary home were linked by means of carefully spaced tees to this chiller loop. Nelson Mechanical Design A Daikin Altherma being raised out. This made good sense as each chiller would see chiller loop temperature and cycle on and off to preserve their setpoint. No thermometers had actually been set up so the initial specialist didn’t understand that the return water from the primary home was blending with the cooled loop supply water and jeopardizing cooling capability for the whole home. Due to the fact that the carefully spaced tees were in reverse, we determined 42 ° F in the chiller loop and 48 ° F for the supply water increasing to your house. Yikes! That was a simple repair with press fittings; we included thermometers so we might see our cooled water temperature levels. Mech Room Design Confusion Insulating a cooled water supply is a difficult task and it was an embarassment to need to remove all of this good insulation off to make our piping modifications. We instantly kept in mind that the system as it was set up was blending return water from the air handlers with cooled supply of water showing up from the chiller pit. As in the chiller pit, this piping confusion jeopardized the cooling capability for the whole home. Nelson Mechanical Design Outside, the carefully spaced tees are in reverse in the chiller pit. The existing Grundfos Magna circulator linked the remote chiller pit 300 feet away with this mechanical space– our pressure drop estimations informed us that it was big enough to supply the essential circulation in between the chiller pit with the 3 5-ton chillers and the cooled water supply of your house. Each of the 4 air handlers had its own cooled water circulator. Due to insufficient pipeline size in between this mech space and the 4 air handlers each of these circulators would require to be changed with a bigger system. The 2 existing buffer tanks were beginning to rot out so they would require to be changed. And Even More Design Confusion! Nelson Mechanical Design Seriously baffled piping in the mechanical space together with insulation. At each of the 4 air handlers, we removed back the pipeline insulation to expose more style confusion. Each of the 4 air handlers had its own cooled water circulator in the mech AND its own three-way zone valve at the coil. Why utilize both? We believed that possibly the air handlers were set up initially and the idea might have been that the Magna circulator would be big enough to do ALL of the pumping. When they figured that it would not have the ability to deal with all of the circulation they included a circulator to each air handler zone. Nelson Mechanical Design Corrected mechanical space insulated for cooled water. In any occasion, the Cv through this Taco three-way valve was badly low and this was another traffic jam that decreased cooled water circulation through the air handler coils. We found that all of the cooled water coils were piped in backwards! Going into water was entering into the coil nearest the return air and leaving water was leaving the coil on the air supply side, which suggested that leaving water temperatures remained in the low 60s, and discharge air temperatures remained in the low 60s. We likewise kept in mind that there were no thermometers and no air separators. What a dish for insufficient circulation and air bound systems! Mech Room Corrections Nelson Mechanical Design Piping confusion at chiller water coils with three-way valves. As soon as we had actually completed our examination, the re-design and re-pipe was enjoyable and simple. We set up a brand-new buffer tank and detached the blending of cooled supply of water originating from the chiller pit with air handler return water. We linked the Magna circulator to the buffer tank and the chiller pit 300 feet away and set up bigger circulators for each air handler zone. We linked the supply for the 4 brand-new circulators to the buffer tank so each zone would get 44 F water. We insulated our work utilizing Armaflex rather of fiberglass insulation. Air Handler Corrections At each of the 4 air handlers, we sliced out the three-way Taco zone valves and piped supply and return lines straight to the cooled water coil. Each air handler likewise got an air separator and thermometers before and after the cooled water coil. We ended up with Armaflex insulation. Chiller Pit Replacement The tail end of our work was to change the unsuccessful Daikin Altherma with a brand-new 5 heap Aermec heat pump/chiller. We detached the Daikin from the chiller loop and pulled it out with an excavator and carefully dropped in the brand-new Aermec. Daikin and Aermec do not talk to each other so we had to set up an HBX staging control to manage staging on and off the 3 systems. Success! Nelson Mechanical Design Thermometers and insulation total the piping corrections. We got the repair work done before summertime showed up and had a month to validate circulation and operation. We changed all 6 of the thermostats with Venstar wifi thermostats that had the ability to manage humidification, dehumidification, heating & cooling. We had the ability to utilize their re-heat function to enhance dehumidification capability. The house owner showed up and the system was tested. Chilled water at each air handler was now 44 ° F like it ought to be. Release air temperature level was now at 52 ° F which was well listed below the dewpoint. Relative humidity in your home dropped and dropped from 75% to 40%. Despite the fact that it was damp and hot outdoors, the property owner was cool and dry within. We kept in mind that all 3 chillers were running throughout start-up as we had actually lastly linked them effectively to the cooling load of your home. The house owner enjoyed– another effective cooled water rescue!
- Wed. Apr 23rd, 2025
Latest News