AVTQ Flow-Compensated Temperature Controller

AVTQ is a self-acting flow-compensated temperature controller primarily for use in district heating systems with plate heat exchangers for instantaneous hot water production. 

It closes on rising sensor temperature. It has permanent no-load (idle) temperature setting on about 40° C which is offset by a pilot valve using flow-compensation principle during tapping. Tapping temperature can be set individually. 

AVTQ prevents high temperatures in the heat exchanger when no hot water is tapped by rapidly shutting off the heat supply (e.g. hot district heating water). 

AVTQ can be used with most plate heat exchangers. However, the heat exchanger manufacturer should be contacted to ensure that the chosen heat exchanger has been approved for use with the AVTQ. 

AVTQ controller consist of a thermostatic actuator, diaphragm element, main valve and pilot valve. 

Thermostatic actuator with diaphragm element and main valve are installed on the district heating (primary) side. The diaphragm element is, via impulse tubes, connected to the pilot valve on the domestic hot water (secondary) side.