Date: Mon, 02 Jan 2006 01:48:17 +0100 From: MH <nonospamo> Subject: Re: Curious Heater Problem
> .. if you reduce the parrallel paths from 2 to one, and > maintain the same pump pressure, the amount of flow through the > remaining path will be increased. I do not know how you define 'amount of flow', but flow rate Q is defined as a volume passing throug a surface area in a certain time; e.g. litres/sec or m3/hr. With the same pump at same rpm and the same flow rate, if you close one leg of the parallel path, the same flow Q will go through a smaller area, at higher speed; if you half the area, the _speed_ will double. If hot water flows through a radiator at higher speed, its retention time in the radiator is less, and it will release less heat to the passing air. For the flow speed to be as slow as possible, you would want the radiator to have an as large as possible flow through area (for both water and air). The thermostat changes nothing to the pump's flow rate, it just opens to divert part of the flow out of the block to the radiator, instead of directly back to the pump. -- MH '72 97 '77 96 '78 95 '79 96 '91 900i