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Tech Talk with John Wilson from Ravenheat plate heat exchangers

WEBVTT
Kind: captions
Language: en

00:00:00.060
good morning guys John Wilson um I'm
00:00:04.010 00:00:04.020 back again I just want to do a video on
00:00:08.890 00:00:08.900 removal of plenty text changes or
00:00:11.270 00:00:11.280 basically the unnecessary to remove
00:00:13.310 00:00:13.320 blood play key text changes and one of
00:00:16.310 00:00:16.320 the major call-outs that you guys get is
00:00:20.300 00:00:20.310 fluctuating hot water with a basic - the
00:00:22.730 00:00:22.740 waters were in hot and cold and your
00:00:24.980 00:00:24.990 customer can be jumping in as a shower
00:00:26.900 00:00:26.910 like a rabbit's nose in and out in and
00:00:29.029 00:00:29.039 out hot cold hot cold well obviously not
00:00:32.510 00:00:32.520 t-shirt is soaked eggs in any shape or
00:00:34.130 00:00:34.140 form but that's usually down to a block
00:00:36.319 00:00:36.329 plate heat exchanger and that block
00:00:38.090 00:00:38.100 block plate he tested is not a boiler
00:00:39.889 00:00:39.899 fault it's deadly that's within the heat
00:00:41.780 00:00:41.790 exchanger I've done some some drawings
00:00:46.580 00:00:46.590 here to play pedestrians and I've got a
00:00:48.369 00:00:48.379 down heat exchanger for you guys
00:00:50.990 00:00:51.000 just to look at now here we've got a
00:00:54.200 00:00:54.210 plate heat exchanger of 82 degrees
00:00:56.060 00:00:56.070 coming in and let's say for instance Flo
00:01:00.229 00:01:00.239 86 coming out really that can't happen
00:01:03.770 00:01:03.780 but we'll address that shortly here
00:01:06.350 00:01:06.360 we've got a heat exchange with 80
00:01:07.730 00:01:07.740 degrees C coming in and 70 degrees C
00:01:10.219 00:01:10.229 coming out here we've got 81 degrees C
00:01:13.399 00:01:13.409 coming in and 45 degrees C coming out
00:01:16.690 00:01:16.700 now these two differential clumps here
00:01:20.960 00:01:20.970 guys these are clumped on to a piece of
00:01:23.480 00:01:23.490 copper pipe so basically the
00:01:26.060 00:01:26.070 differential between these two the the
00:01:28.130 00:01:28.140 instrumentation that we color is not
00:01:29.960 00:01:29.970 accurate enough to get a readable for
00:01:31.730 00:01:31.740 the differential because it's a pipe so
00:01:33.770 00:01:33.780 the temperature is the same across that
00:01:35.420 00:01:35.430 pipe when we're doing a differential
00:01:37.280 00:01:37.290 reading when we've come to a heat
00:01:39.440 00:01:39.450 exchanger heat exchanger in its own
00:01:41.780 00:01:41.790 definition it exchanges heat that's what
00:01:44.210 00:01:44.220 it does okay
00:01:45.410 00:01:45.420 now the reason for this violet well you
00:01:48.950 00:01:48.960 will you've got a boil that's firing up
00:01:50.330 00:01:50.340 and dropping out going hot and cold
00:01:51.740 00:01:51.750 always make sure that the burner is
00:01:53.539 00:01:53.549 actually dropping out guys this 82
00:01:56.899 00:01:56.909 degree C is very very important and if
00:01:59.450 00:01:59.460 we looked at these heat exchangers this
00:02:01.550 00:02:01.560 one is one that's working there is a
00:02:03.139 00:02:03.149 level of debris in this one but this one
00:02:05.660 00:02:05.670 is working pretty decent because we've
00:02:07.520 00:02:07.530 got 81 degrees C coming in
00:02:09.770 00:02:09.780 and 45 degrees say coming out this one
00:02:12.440 00:02:12.450 is way off because we've only got a 10
00:02:14.480 00:02:14.490 degree differential so basically it's
00:02:16.760 00:02:16.770 not becoming a heat exchangers becoming
00:02:18.590 00:02:18.600 a pipe and this one is very involved
00:02:20.809 00:02:20.819 with a 2 degree C coming in and a hotter
00:02:22.760 00:02:22.770 temperature coming out now we exchange
00:02:26.479 00:02:26.489 the water the cold water comes into the
00:02:28.250 00:02:28.260 heat exchanger the flow from the space
00:02:30.890 00:02:30.900 heating as the diverter valve moves
00:02:33.140 00:02:33.150 across obviously we're getting the
00:02:34.850 00:02:34.860 transfer of heat okay now as the level
00:02:38.750 00:02:38.760 of debris comes more severe in this heat
00:02:41.240 00:02:41.250 exchanger the differential temperature
00:02:43.190 00:02:43.200 gets less and less and less and just
00:02:46.430 00:02:46.440 just to put it in simple terms basically
00:02:48.320 00:02:48.330 all we're doing guys we're changing the
00:02:50.630 00:02:50.640 heat exchanger into a pipe and why are
00:02:52.970 00:02:52.980 we turning into a fight because we just
00:02:54.650 00:02:54.660 will get to the stage where one single
00:02:56.360 00:02:56.370 track through the heat exchanger so it's
00:02:58.370 00:02:58.380 no longer an exchange in heat so the
00:03:00.530 00:03:00.540 course of action there's take the heat
00:03:02.270 00:03:02.280 exchanger out and give it a good
00:03:03.559 00:03:03.569 planners now the reason for the video
00:03:06.440 00:03:06.450 guys is there is so many plate exchanges
00:03:09.890 00:03:09.900 that take now unnecessary and how many
00:03:12.259 00:03:12.269 times have you done it where you've been
00:03:14.090 00:03:14.100 with your customer you value Bukit
00:03:15.920 00:03:15.930 they're ready to show the custom of the
00:03:17.449 00:03:17.459 debris and surprise surprise you look at
00:03:19.789 00:03:19.799 cloud because there's no debris in there
00:03:21.410 00:03:21.420 well there's a couple of checks that you
00:03:23.600 00:03:23.610 need to do before you start dragging
00:03:25.280 00:03:25.290 plate experiences out the boilers and it
00:03:27.650 00:03:27.660 will save you a lot of time if you if
00:03:29.240 00:03:29.250 you heed what I'm saying now on a boiler
00:03:32.780 00:03:32.790 we have the space heating the midst of
00:03:34.430 00:03:34.440 the primary thermistor what you'll call
00:03:36.050 00:03:36.060 and this is on the the central heating
00:03:38.270 00:03:38.280 flow when the diverter valves in the
00:03:40.699 00:03:40.709 heating mode this pipe supplies this
00:03:42.470 00:03:42.480 space heating women in domestic hot
00:03:44.210 00:03:44.220 water the diverter valve mechanism moves
00:03:46.640 00:03:46.650 across and we move it to supply the
00:03:49.009 00:03:49.019 plate now the central heating thermistor
00:03:51.650 00:03:51.660 has three functions the first function
00:03:54.710 00:03:54.720 is for temperature and modulation of the
00:03:56.300 00:03:56.310 heating the second function is built-in
00:03:59.750 00:03:59.760 frost protection at 10 degrees the pump
00:04:01.849 00:04:01.859 energizes at 5 degrees of the burner
00:04:04.370 00:04:04.380 will fire and raise it to 25 degrees C
00:04:07.069 00:04:07.079 so it's 5 stanton frost on one and
00:04:09.199 00:04:09.209 that's across most vile as these days
00:04:11.060 00:04:11.070 now
00:04:12.020 00:04:12.030 the third function is very important
00:04:14.330 00:04:14.340 it's high limit and high limit is rated
00:04:17.539 00:04:17.549 between 82 and 85 degrees and that's
00:04:20.690 00:04:20.700 pretty much the standard in the industry
00:04:22.360 00:04:22.370 guys so the high limit is what kicks in
00:04:25.120 00:04:25.130 when the burner actually drops out so
00:04:26.950 00:04:26.960 that's why the customer gets hot and
00:04:28.510 00:04:28.520 cold water because it's the high limit
00:04:30.550 00:04:30.560 staff that's reaching 82 because why is
00:04:33.070 00:04:33.080 this getting so hot it can't dissipate
00:04:35.500 00:04:35.510 the heat because the plate heat
00:04:36.790 00:04:36.800 exchangers bundle with debris so that's
00:04:38.890 00:04:38.900 the reason for it dropping now it's the
00:04:40.390 00:04:40.400 high limit that that dictates that okay
00:04:42.790 00:04:42.800 now one thing the couple of things that
00:04:45.969 00:04:45.979 you must do are I'm not saying most I
00:04:49.320 00:04:49.330 recommend that you do okay this isn't
00:04:52.990 00:04:53.000 all that much very compliance and this
00:04:55.960 00:04:55.970 is a standard holy world gas valve along
00:04:58.120 00:04:58.130 this gas valve we have a plastic notes
00:05:01.000 00:05:01.010 and we have a brass note okay the
00:05:03.250 00:05:03.260 plastic that the blast note is the low
00:05:05.050 00:05:05.060 burner pressure the plastic note is the
00:05:06.790 00:05:06.800 high burner pressure now with a gas
00:05:10.600 00:05:10.610 valve the high burner pressure is
00:05:12.909 00:05:12.919 controlled by the thermistor and the
00:05:15.370 00:05:15.380 setting the low burner pressure on Iran
00:05:17.469 00:05:17.479 old atmospheric violence guys is purely
00:05:19.750 00:05:19.760 a manual setting so let's say this
00:05:21.760 00:05:21.770 particular boiler the low burner presses
00:05:23.890 00:05:23.900 to millibar on domestic hot water and
00:05:25.689 00:05:25.699 heating and the hive is 11.2 now let's
00:05:30.310 00:05:30.320 say for instance that somebody has set
00:05:32.770 00:05:32.780 that low burner pressure far too high if
00:05:35.020 00:05:35.030 the set that far too high we've got a
00:05:37.240 00:05:37.250 big problem there because basically it
00:05:40.029 00:05:40.039 won't modulate so when the customers
00:05:42.400 00:05:42.410 running hot water
00:05:43.240 00:05:43.250 that's why there'll be problems with it
00:05:44.950 00:05:44.960 going hot and cold it's not the
00:05:46.510 00:05:46.520 platelets bond nope it's the low burner
00:05:48.610 00:05:48.620 pressure that's too high so you've wiped
00:05:50.320 00:05:50.330 out the modulation and basically the
00:05:52.270 00:05:52.280 pipe with the primary thermistor will
00:05:53.950 00:05:53.960 get hot and it would mimic the plate
00:05:55.930 00:05:55.940 heat exchanger being blocked the other
00:05:58.360 00:05:58.370 thing that you must check so that's one
00:06:00.040 00:06:00.050 point to try and remember this will say
00:06:02.350 00:06:02.360 the hours in your career the other thing
00:06:04.540 00:06:04.550 to remember here I've got a thermistor
00:06:07.089 00:06:07.099 sheet if you just pump down onto the
00:06:09.370 00:06:09.380 sheet if you can if you can't get this
00:06:11.920 00:06:11.930 then how the we'll gladly send it on
00:06:14.200 00:06:14.210 this thermistor sheet here I've got a
00:06:15.850 00:06:15.860 clip on thermistor the multimeter here
00:06:23.730 00:06:23.740 one thing with multimeters I suggest if
00:06:28.150 00:06:28.160 you don't Foley on

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