diff --git a/code/html/src/sensor.mjs b/code/html/src/sensor.mjs
index 8103c202..c3b8c663 100644
--- a/code/html/src/sensor.mjs
+++ b/code/html/src/sensor.mjs
@@ -12,6 +12,7 @@ import {
     prepareEnumerableTarget,
     resetGroupElement,
     setChangedElement,
+    setIgnoredElement,
     setOriginalFromValue,
     setSelectValue,
     variableListeners,
@@ -428,6 +429,7 @@ function initMagnitudesExpected(id) {
     expected.name += info.key;
     expected.id = expected.name;
     expected.dataset["id"] = info.id.toString();
+    setIgnoredElement(expected);
 
     const [message] = /** @type {NodeListOf<HTMLSpanElement>} */
         (template.querySelectorAll(`span.emon-expected-${info.prefix}`));
diff --git a/code/html/src/settings.mjs b/code/html/src/settings.mjs
index 44bc66a4..94557df2 100644
--- a/code/html/src/settings.mjs
+++ b/code/html/src/settings.mjs
@@ -54,7 +54,7 @@ export function resetChangedElement(elem) {
  * @param {HTMLElement} elem
  */
 function resetGroupPending(elem) {
-    elem.dataset["settingsGroupPending"] = "";
+    delete elem.dataset["settingsGroupPending"];
 }
 
 // Right now, group additions happen from:
@@ -137,16 +137,34 @@ export function resetGroupElement(elem) {
 
 /**
  * @param {HTMLElement} elem
+ * @returns {boolean}
  */
 export function isGroupElement(elem) {
     return elem.dataset[SETTINGS_GROUP_ELEMENT] !== undefined;
 }
 
+const SETTINGS_IGNORED_ELEMENT = "settingsIgnore";
+
 /**
  * @param {HTMLElement} elem
  */
-function isIgnoredElement(elem) {
-    return elem.dataset["settingsIgnore"] !== undefined;
+export function setIgnoredElement(elem) {
+    elem.dataset[SETTINGS_IGNORED_ELEMENT] = "true";
+}
+
+/**
+ * @param {HTMLElement} elem
+ */
+export function resetIgnoredElement(elem) {
+    delete elem.dataset[SETTINGS_IGNORED_ELEMENT];
+}
+
+/**
+ * @param {HTMLElement} elem
+ * @returns {boolean}
+ */
+export function isIgnoredElement(elem) {
+    return elem.dataset[SETTINGS_IGNORED_ELEMENT] !== undefined;
 }
 
 /**
@@ -432,6 +450,22 @@ function groupSettingsCleanup(container, keys) {
  * @typedef {{[k: string]: DataValue}} SetRequest
  */
 
+/**
+ * @param {string | number |boolean} value
+ * @returns {DataValue}
+ */
+function maybeAdjustDataValue(value) {
+    if (typeof value === "boolean") {
+        return value ? 1 : 0;
+    }
+
+    if (typeof value === "number" && isNaN(value)) {
+        return "nan";
+    }
+
+    return value;
+}
+
 /**
  * specific 'key' string to remove from the device settings storage
  * @typedef {string} DelRequest
@@ -478,6 +512,10 @@ export function getData(forms, {cleanup = true, assumeChanged = false} = {}) {
                 continue;
             }
 
+            if (elem instanceof HTMLInputElement && elem.readOnly) {
+                continue;
+            }
+
             const name = elem.dataset["settingsRealName"] || elem.name;
             if (!name) {
                 continue;
@@ -506,11 +544,8 @@ export function getData(forms, {cleanup = true, assumeChanged = false} = {}) {
                 const data_name = group_element
                     ? group_name : name;
 
-                // TODO small value optimization, so booleans always take 1 byte in the resulting json
-                const data_value = (typeof value === "boolean")
-                    ? (value ? 1 : 0) : value;
-
-                data[data_name] = data_value;
+                // fixing outgoing data, when it is necessary
+                data[data_name] = maybeAdjustDataValue(value);
             }
         }
     }
diff --git a/code/html/src/template-sns.html b/code/html/src/template-sns.html
index b757ba78..08418e75 100644
--- a/code/html/src/template-sns.html
+++ b/code/html/src/template-sns.html
@@ -28,7 +28,7 @@
         </div>
         <div class="pure-control-group">
             <label>Expected value</label>
-            <input name="expected:" type="text" class="emon-expected-input">
+            <input name="expected:" type="text" class="emon-expected-input" data-action="none">
             <span class="pure-form-message-inline hidden emon-expected-pwrP">
                 In Watts (W). Calibrate your sensor connecting a pure resistive load (like a bulb) and enter here its nominal power or use a multimeter.
             </span>
diff --git a/code/html/src/validate.mjs b/code/html/src/validate.mjs
index ed4f3ed4..d7f7c845 100644
--- a/code/html/src/validate.mjs
+++ b/code/html/src/validate.mjs
@@ -1,4 +1,4 @@
-import { isChangedElement, getElements } from './settings.mjs';
+import { isChangedElement, isIgnoredElement, getElements } from './settings.mjs';
 import { showPanel } from './core.mjs';
 import {
     formPassPair,
@@ -126,7 +126,7 @@ export function validateFormsPasswords(forms, {strict = true, assumeChanged = fa
 export function validateFormsReportValidity(forms) {
     const elems = forms
         .flatMap((form) => getElements(form))
-        .filter(isChangedElement)
+        .filter((x) => isChangedElement(x) && !isIgnoredElement(x))
 
     if (!elems.length) {
         return false;